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APPLIED  ANATOMY 

THE  CONSTRUCTION  OF  THE  HUMAN  BODY 

CONSIDERED   IN 

RELATION  TO   ITS  FUNCTIONS, 
DISEASES,  AND  INJURIES 


BY 

GWILYM    G.  DAVIS 

ASSOCIATE     PROFESSOR    OF     APPLIED     ANATOMY,    UNIVERSITY    OF     PE.N'NSYLVANI. 


UNIVERSITIES    OF    PENNSYLVANIA    AND    GOETTINGEX;      MEMBER    OF     THE    ROYAL    COLLEGE    OF    SURi 
ENGLAND;     SURGEON    TO    THE     EPISCOPAL,    ST.    JOSEPH'S.     AND     ORTHOPAEDIC     HOSPITALS;      ORTHOP. 
SURGEON    TO    THE    PHILADELPHIA    GENERAL    HOSPITAL;     FELLOW  OF    THE    AMERICAN    SURGICAL 
association;    member  of  the  society  OF   CLINICAL  SURGERY;    MEMBER   OF    THE 
AMERICAN   ORTHOPEDIC    ASSOCIATION;    FELLOW    OF    THE    PHILA- 
DELPHIA    ACADEMY     OF     SURGERY,    THE    PHILADELPHIA 
COLLEGE    OF    PHYSICIANS,  AND    THE     AMERICAN 
ACADEMY   OF   MEDICINE,    ETC. 


WITH  SIX  HUNDRED  AND  THIRTY  ILLUSTRATIONS,  MOSTLY 
FROM   ORIGINAL   DISSECTIONS   AND   MANY   IN  COLOR 


ERWIN  F.  FABER 


PHILADELPHIA  ^   LONDON 

J.  B.  LIPPINCOTT    COMPANY 


Mss 


Copyright,   1910 
By  J.   B.   I.ippiNcoTT  Company 


2. 


Printed  by  J.   B.   Lippincott  Company 
The   Washington  Square  Press,   Philadelphia,   U.  S.  A. 


en 


To 


.GEORGE  A.  PIERSOL,  M.D.,  Sc.D. 

PROFESSOR  OF  ANATOMY  IN  THE   UNIVERSITY  OF   PENNSYLVANIA, 
AN   IDEAL  SCIENTIST,  TEACHER,  AND  FRIEND 


Digitized  by  the  Internet  Archive 

in  2010  with  funding  from 

Open  Knowledge  Commons 


http://www.archive.org/details/appliedanatomyco1910davi 


PREFACE, 


It  is  not  the  object  of  this  work  to  teach  plain  anatomical  facts  ;  its  aim  is  to 
show  the  relation  of  structure  to  function,  whether  it  is  normal  function  or  function 
disturbed  or  impaired  by  injury  or  disease.  It  is  explanatory  and  utilitarian  in 
character,  and  not  encyclopedic.  The  bare  facts  of  anatomy  can  be  obtained  from 
the  systematic  treatises,  and  they  are  here  onljr  briefly  given  in  order  to  refresh  the 
memory  of  the  reader,  who  is  supposed  to  be  familiar  to  a  certain  extent  with 
systematic  anatomy.  A  person  who  has  studied  the  subject  only  from  a  systematic 
standpoint  cannot  utilize  and  apply  the  knowledge  so  acquired  unless  he  considers 
its  relation  to  the  various  affections  encountered  in  practice.  He  can  study  anatomy, 
but  he  will  not  see  its  application  until  it  is  pointed  out  to  him.  He  may  have 
studied  the  palmar  fascia,  but,  unless  he  is  shown  how  its  construction  influences  the 
course  of  pus  originating  beneath  it,  his  anatomical  knowledge  is  of  little  value. 
The  inability  to  make  any  practical  use  of  the  facts  or  to  see  their  application  is  the 
reason  why  anatomy  is  so  frequently  regarded  as  a  dry,  uninteresting  study  and  too 
often  designedly  neglected. 

In  considering  the  subject,  after  a  few  general  remarks  on  the  part  involved,  the 
skeleton  and  muscles  are  briefly  described,  and  thereby  one  is  enabled  to  understand 
the  surface  anatomy,  which  immediately  follows.  Then  comes  a  consideration  of  the 
various  affections  of  the  part,  with  such  allusion  to  the  ner\-es  and  \'essels  as  is  desir- 
able to  elucidate  the  subject.  As  the  book  is  not  intended  to  be  a  systematic 
treatise  on  anatomy,  such  anatomical  facts  as  cannot  be  shown  to  be  useful  in  practice 
are  not  mentioned.  To  gi\-e  them  here  would  make  the  \'olume  too  large,  obscure 
its  main  object,  and  defeat  its  purpose. 

As  regards  the  anatomical  nomenclature  used,  there  is  no  system  so  generally 
accepted  as  to  justify  its  exclusive  adoption.  In  the  desire,  however,  to  aid  in  further- 
ing the  adoption  of  better  anatomical  terms,  as  much  of  the  BNA  terminology  has 
been  used,  or  included  in  parentheses,  as  a  consideration  of  the  subject  from  the 
standpoint  of  a  general  practitioner  would  allow. 

Most  of  the  illustrations  are  from  original  drawings  of  preparations  made  by  the 
author  and  his  assistants.  Those  deri\'ed  from  other  sources  are  duly  credited  ;  if 
there  has  been  any  failure  in  this  respect,  it  is  unintentional. 

The  clinical  material,  except  where  otherwise  stated,  is  from  the  author's  own 
experience. 

To  the  artist  in  charge,  Mr.  Erwin  F.  Faber,  and  to  Mr.  Herman  Faber,  who 
made  a  large  number  of  the  original  sketches,  my  best  thanks  are  due  for  their  great 
skill,  untiring  energy,  and  most  intelligent  aid  ;  their  work  speaks  for  itself. 


vi  PREFACE. 

I  am  under  great  obligations  to  many  friends  who  have  kindly  rendered  me  their 
aid.  Professor  George  A.  Piersol  has  given  me  much  valuable  information  and 
allowed  me  the  unstinted  use  of  his  anatomical  material  ;  Dr.  Astley  P.  C.  Ashhurst 
made  many  of  the  dissections  and  aided  in  correcting  and  preparing  the  manuscript 
for  the  press  ;  Dr.  Frank  D.  Dickson  did  most  of  the  proof-reading  and  prepared  the 
index  ;  Dr.  T.  Turner  Thomas  made  many  of  the  earlier  preparations  ;  and  Dr.  Henry 
Beates  aided  in  the  revision  of  the  first  portion  of  the  manuscript.  To  these  and 
others  who  have  contributed  to  the  formation  of  the  book  I  desire  to  express  my 
thanks. 

To  the  hearty  cooperation  and  unfailing  generosity  of  m)-  publishers  is  due  the 
presentation  of  such  an  attractive  volume.  I  asked  them  for  nearly  everything  I 
could  think  of,  and  they  gave  me  nearly  everything  I  asked  for. 

In  conclusion  :  this  work  is  recognized  as  being  far  from  complete,  but  it  is 
intended  to  be  suggestive  rather  than  absolute.  It  is  not  designed  so  much  to 
present  facts  as  to  furnish  reasons,  and  it  is  hoped  that  it  will  appeal  to  the  practising 
physician  and  surgeon  as  well  as  to  the  student. 

GwiLYM  G.  Davis. 
Phil.vdelphia,  August,  1910. 


CONTENTS, 


THE    SCALP.  Page 

Skin..., I 

Superficial  Fascia i 

Occipitofrontalis  Muscle 2 

Subaponeurotic  Tissue 2 

Pericranium 2 

Subpericranial  Tissue 2 

Arteries  of  the  Scalp 3 

Temporal  Artery 3 

Occipital  Artery 3 

Lymphatics  of  the  Scalp 4 

Affections  of  the  Layers  of  the  Scalp.  ...  4 

Affections  of  the  Blood-vessels 6 

Treatment  of  Vascular  Affections  of  the 

Scalp 7 

Tumors  of  the  Scalp 7 

THE  SKULL. 

The  Skull  in  Childhood 8 

Fontanelles 8 

Dura  Mater 9 

The  Skull  in  Adults 10 

Tables 10 

Sutures 10 

Frontal  Sinuses 10 

Mastoid  Process i  r 

Suprameatal  Triangle 12 

Cerebral  Venous  Sinuses 12 

Fractures  of  the  Skull 14 

Fractures  of  the  Skull  in  Children.  .  14 

Fractures  of  the  Skull  in  Adults. ...  15 
Fractures  by  Contrecoup  or  Counter 

Stroke 16 

Hemorrhage    in    Fractures    of    the 

Skull 16 

Injuries   to   Nerves   in   Fracture  of 

the  Skull u) 

THE  MENINGES. 

Dura  Mater 20 

Arachnoid 21 

Pia  Mater 22 

Affections    of    the     Membranes    of    the 

Brain 22 

Pachymeningitis 22 

Dural  Hemorrhage 23 

Meningitis .' .  23 

Pial  Hemorrhage 23 

THE  BRAIN. 

Circulation  of  the  Brain 25 

Internal  Carotid  Artery 27 

Anterior  Cerebral  Artery 27 

Middle  Cerebral  Artery 28 

Posterior  Cerebral  Artery 28 

Cerebral  Softening 30 

Apoplexy 30 

Crossed  Paralysis 32 

Cortical  Apoplexy 32 

Cerebral  Lobes:  Frontal,  Parietal,  Occip- 
ital, Temporosphenoidal,  Central  Lobe 

or  Island  of  Reil 32 


Page 
Fissures  and  Convolutions  of  the  Brain.  .  33 
Lateral  Surface  of  the  Hemispheres  ....  33 
Medial  Surface  of  the  Hemispheres  ...  34 
Functions  of  the  Cortex  of  the  Brain: 

Cerebral   Localization 34 

Functions  of  the  Convolutions  on  the 
surface  of  the  Cerebrum:  Prefrontal 
Area;  Midfrontal  Area;  Speech 
Centre  or  Broca's  Convolution;  Post- 
frontal  Area;  Rolandic  Area;  Sensory 
Area;  Visual  Area;  Auditory  Area; 
Gustatory  Area;    Olfactory  Area.  ...      35 

Functions  of  the  Basal  Ganglia 37 

Corpus  Striatum  and  Thalamus.  ...      37 
Corpora  Quadrigemina,  Crura  Cere- 
bri, Pons  Varolii 38 

The  Corona  Radiata,  Internal  Capsule, 

and  Motor  Tract 38 

Craniocerebral  Topography 39 

Bony   Landmarks;      Topographical 

Points 40 

The  Lower  Level  of  the  Brain 40 

Fissures  and  Convolutions 40 

Subsidiary  Fissures,  Convolutions  .      41 

The  Fissures  in  Children 42 

The  Lateral  Ventricles 43 

Cerebral  Abscess — Trephining 44 

THE   FACE. 

The  Frontal  Region 45 

The  Temporal  Region 46 

The  Temporal  Fascia 47 

The  Region  of  the  Cheek 49 

Parotid  Gland 51 

The  Upper  Jaw 54 

The  Lower  Jaw 63 

The  Region  of  the  Eye 72 

The  Eyeball  and  Optic  Nerve 77 

The  Eyelids  and  Conjunctiva 82 

The  Lachrymal  Apparatus .  .  83 

The  Ear 84 

Operations  on  the  Middle  Ear 90 

The  No.se 94 

Frontal  Sinus loi 

Ethmoidal  Sinuses 102 

Sphenoidal  Sinus,  Ma.xillary  Sinus.  .  103 

THE  MOUTH  AND  THROAT. 

The  Tongue 107 

Roof  of  Mouth 

Palatal  Arches 

Faucial  Tonsils 

Retropharyngeal  Abscess 

The  Pharynx 

Eustachian  Tube. 

Pharyngeal  Tonsil 

The  Larynx 


THE  NECK. 

Surface  Anatomy 

Cervical  Triangles 

Torticollis 


12S 

131 
140 


CONTENTS. 


Ligation  of  Arteries 141 

The  Cervical  Fascias 150 

Lymphatics  of  the  Neck 156 

Operations  on  the  Air  Passages 161 

Operations  on  the  Thyroid  Gland 163 

The  Parathyroid  Bodies 165 

(Esophagus — Cervical  Portion 166 

Cut- throat 168 

AiTections  of  the  Neck 169 

THE  THORAX. 

Sternum,  Ribs,  and  Costal  Cartilages  .  .  174 

Thoracic  Vertebras 176 

Soft  Parts  of  Chest 176 

Muscles  of  Chest 177 

Surface  Anatomy  of  Thora.K iSo 

Breast  or  Mamma 1S2 

Lymphatics  of  Breast 184 

Abscess  of  Breast;    Tumors 185 

Excision  of  Breast 187 

The  Mediastinum 187 

Pleural  EiTusions 191 

The  Chest  Contents 192 

Longitudinal  lines;  Regions 192 

The  Pleurte 194 

The  Lungs 196 

Pericardium 201 

The  Heart 204 

The  Aorta 208 

The  CEsophagus 211 

The  Thoracic  Duct 214 

THE  UPPER  EXTREMITY. 

The  Shoulder-Girdle 217 

Bones  of  the  Shoulder 219 

Shoulder- Joint 222 

Muscles  of  the  Shoulder 226 

Surface  Anatomy 227 

Axilla 229 

Dislocations  of  the  Clavicle 230 

Dislocations  of  the  Shoulder 232 

Fractures  of  the  Clavicle 241 

Fractures  of  the  Scapula 243 

Fractures  of  the  Upper  end  of  the  Hu- 
merus      244 

Epiphyseal  Separations 247 

Amputation  at  the  Shoulder-Joint 247 

Interscapulothoracic  Amputation 250 

Excision  of  the  Clavicle 250 

Excision  of  the  Scapxila   251 

Excision  of  the  Head  of  the  Humerus .  .  251 

Diseases  of  the  Shoulder-Joint  and  Bursa;  253 

Axillary  Vessels 257 

Axillary  Lymphatics 263 

Abscesses  of  Axilla 264 

THE  ARM. 

The  Humerus 267 

Muscles  of  the  Arm 267 

Intermuscular  Septa 271 

Surface  Anatomy 271 

Brachial  Artery 272 

Amputation  of  the  Arm 275 

Fractures  of  the  Humerus 276 

Operations  on  the  Arm 279 

REGION  OF  THE   ELBOW. 

Bones  of  the  Elbow 280 

Elbow-Joint 282 

Muscles  of  the  Elbow 284 


Page 

Surface  Anatomy 287 

Veins  of  the  Elbow 28S 

Brachial  Artery 290 

Dislocations  of  the  Elbow 291 

Fractures  in  the  Region  of  the  Elbow.  .  .  295 
Diseases  of  the  Olecranon  Bursa;  Diseases 

of  the  Elbow-Joint 300 

Resection  of  the  Elbow 301 

Amputation  at  the  Elbow 302 

THE  FOREARM. 

Bones 303 

Movements  of  Pronation  and  Supination  304 

Muscles 305 

Surface  Anatomy 312 

Arteries 3  14 

Nerves 317 

Fractures 321 

Amputation 326 

Operations 328 

REGION  OF  THE  WRIST. 

Bones  of  the  W"rist 330 

Inferior  Radio-ulnar  Articulation 332 

Wrist-Joint 333 

Anterior  Annular  Ligament 335 

Posterior  Annular  Ligament 336 

Surface  Anatomy  of  the  Wrist 338 

Compound  Ganglion 342 

Fractures  of  the  lower  end  of  the  Radius 

and  Ulna 342 

Dislocations  at  the  Wrist 345 

Excision  of  the  Wrist 347 

Amputation  at  the  Wrist 347 

THE  HAND. 

Bones  of  the  Hand 349 

The  Phalanges 351 

Joints 352 

Muscles 353 

Surface  Anatomy 354 

Palmar  Fascia 357 

Arteries 358 

Nerves 360 

Dislocations 362 

Fractures 364 

Wounds 364 

Abscesses 365 

Lymphatics 368 

Amputations 368 

THE  ABDOMEN. 

Surface  Anatomy 370 

Abdominal  Viscera 372 

Abdominal  Walls 374 

Muscles  of  the  Abdomen 375 

Vessels  of  the  Abdominal  Walls 378 

Abdominal  Incisions 381 

Herniae 382 

Umbilical 383 

Inguinal  Congenital 383 

Acquired  Inguinal  Hernia 385 

Radical  Cure 387 

Femoral  Hernia 390 

The  Lumbar  Region 392 

Lumbar  Fascia 393 

Lumbar  Abscess 394 

Lumbar  Incisions 395 

The  Interior  of  the  Abdomen 396 

Peritoneum 396 


CONTENTS. 


IX 


Page 

Abdominal  Viscera 399 

Stomach 401 

Affections  of  the  Stomach 403 

Operations  on  the  Stomach.  ...  405 

The  vSmall  Intestine 406 

Duodenum 40S 

Jejunum  and  Ileum;  Operations  409 

The  Mesentery 410 

The  Large  Intestine 411 

Cfficum  and  Appendix 414 

Appendicitis 414 

The  Colon 414 

The  Liver 416 

Wounds  and  Injuries 417 

Abscess 420 

Gail-Bladder  and  Biliary  Passages.  420 

Gall-Stones 422 

The  Pancreas 422 

Cysts  and  Abscesses 423 

The  Spleen 424 

Splenic  Enlargement 424 

Wounds 424 

The  Kidneys 424 

Displacement  of  the  Kidneys.  .  427 

Tumors  of  the  Kidney 427 

Abscess  of  the  Kidney 42  8 

Operations  on  the  Kidney.  .  .  .  428 

The  Suprarenal  Gland 438 

The  Ureter  and  Renal  Pelvis 430 

Operations  on  the  Ureter 43  i 

THE  PELVIS. 

Pelvic  Walls 434 

Pelvic  Floor 435 

Pelvic  Fascia 436 

Iliac  Vessels 438 

Pelvic  Viscera 43  8 

Rectum  and  Anal  Canal 440 

Blood- Vessels 442 

Affections  of  Rectum  and  Anus  442 

Imperforate  Anus 442 

Hemorrhoids 443 

Fistula 443 

Fissure 443 

Excision  of  Rectum 444 

Bladder 447 

Bladder  in  the  Female 448 

Cystoscopic  Examination 448 

Operations  on  the  Bladder.  ...  448 

Prostate 450 

Hypertrophy 450 

Prostatectomy 451 

Abscess 452 

Seminal  Vesicles :.  453 

Vas  Defferens 454 

Development  of  the  Urogenital  System  .  454 

Female  Generative  Organs 454 

Uterus 456 

Ovary 456 

Fallopian  Tubes 457 

Vagina. 457 

Ureter  in  the  Female 458 

Blood-Vessels 458 

Lymphatics 459 

Pelvic  Examinations 459 

Operations  on  the  Female  Pelvic  Organs  460 

Hysterectomy 461 

Oophorectomy 461 

Vaginal  Hysterectomy 462 

The  Female  External  Genitals 462 

Clinical  Considerations 463 

Female  Perineum 464 


Page 

Male  External  Genitals 465 

Penis 465 

Scrotum 467 

Testicles 468 

Epididymis 468 

Spermatic  Cord 469 

Urethra 470 

Muscles 471 

Passage  of  Sounds  and  Cathe- 
ters    471 

The  Male  Perineum 472 

The  Perineal  Fascias. '. 473 

The  Perineal  Spaces 474 

Practical  Application 475 

Rupture  of  the  Urethra 475 

Median -Lithotomy 475 

Lateral  Lithotomy 476 

Anal  Triangle  and   Ischiorectal 

Region 476 

THE  BACK  AND  SPINE. 

Surface  Anatomy 477 

The  Vertebral  Column 478 

Curves 478 

Movements 478 

Deformities  of  the  Spinal  Column.  .  478 

Kyphosis 479 

Lordosis 479 

Scoliosis 479 

Affections  of  the  Spinal  Column.  .  .  481 

Injuries  of  the  Spinal  Column 482 

Spinal  Cord  and  its  Membranes  ....  483 

Transverse  Spinal  Lesions 4S4 

Spinal  Meninges 484 

Spinal  Hemorrhage 486 

Functions     of     the     Cord     and     Spinal 

Localization 4S7 

Lesions  of  the  Cord 4S7 

Operations  on  the  Spine 488 

THE  LOWER  EXTREMITY. 

General  Considerations 489 

The  Bony  Pelvis 489 

Mechanisim  of  the  Pelvis 490 

Fractures  of  the  Pelvis 491 

Attachment  of  the  Lower  Extremities  to 

the  Trunk 491 

Anteroposterior  Equilibrium 492 

Lateral  Equilibrium 493 

Deviations     of    the     Spine     above     the 

Sacrum 495 

Distortions  Accompanying  Affections  of 

the  Lower  Extremities 496 

Measurement  of  the  Lower  Limbs 497 

Walking 49S 

THE   REGION   OF  THE   HIP. 

Bones  of  the  Hip 499 

Muscles  of  the  Hip 503 

Surface  Anatomy 504 

Ligation    of    the    Gluteal,    Sciatic,   and 

Internal  Pudic  Arteries 505 

The  Hip-Joint 506 

Dislocations  of  the  Hip 508 

Mechanism  of  the  Production  of .  .  .  509 

Reduction  of 5x2 

Congenital  Lu.xations  of  Hip 514 

Coxalgia 515 

Hip  Abscess 516 

Coxa  Vara 517 


CONTENTS. 


Page 

Coxa  Valga 517 

Operations  on  the  Hip-Joint 517 

Lateral  Operations 517 

Anterior  Operations 519 

Inferior  Operations 5iq 

THE  THIGH. 

Muscles 520 

Surface  Anatomy 522 

Scarpa's  Triangle 522 

Femoral  Artery 523 

Hunter's  Canal 524 

Long  Saphenous  Vein 525 

Lymphatics 527 

Sciatic  Nerve 527 

Fractures  of  the  Femur 529 

Fracture  of  Neck 529 

Fracture     through     the     Trochan- 
ters   531 

Fracture  of  the  Shaft 53  i 

Amputation  at  the  Hip- Joint 532 

Amputation  of  the  Thigh 532 

REGION  OF  THE  KNEE. 

Surface  Anatomy 533 

The  Knee-joint 534 

Movements 534 

Bones 534 

Ligaments 535 

Bursas  of  the  Knee 538 

Fracture  of  the  Patella 539 

Dislocation  of  the  Patella 540 

Dislocation  of  the  Knee 541 

Dislocation     of     the     Semilunar     Carti- 
lages    541 

Epiphyseal  Separations 541 

Resection  of  the  Knee 542 

Tuberculous     Disease     of      the     Knee- 
joint  543 

Knock- Knee  and  Bow-Legs 543 

Osteotomy 544 

Ligation  of  the  Popliteal  Artery 544 

Amputation  through  the  Knee-joint  .  .  .  S44 

THE  LEG. 

Surface  Anatomy 546 

Muscles  of  the  Leg 546 

Fascia  of  the  Leg 548 

Arteries  of  the  Leg 548 

Veins  of  the  Leg 550 

Varicosities  of 550 

Lymphatics  of  the  Leg 551 

Fractures  of  the  Leg 551 

Amputation  of  the  Leg 552 


REGION  OF  THE  ANKLE. 

P.\GE 

Surface  Anatomy 555 

Ankle-joint 554 

Ligaments 554 

Movements 554 

Tuberculosis  of  the  Ankle 555 

Excision  of  the  Ankle 555 

Sprain  of  the  Ankle 556 

Dislocations  of  the  Ankle 556 

Fractures  of  the  Ankle 557 

Fracture    by     Eversion    or     Pott's 

Fracture 557 

Fracture  by  Inversion 558 

Amputations  at  the  Ankle $^y 

Syme's 559 

Pirogofl's 560 

REGION  OF  THE  FOOT. 

The  Construction  of  the  Foot 561 

Diseases  and  Injuries  of  the  Foot 561 

Treatment  of  Affections  of  the  Feet.  .  .  .  562 

Bones  of  the  Foot 562 

Arch  of  the  Foot 563 

Joints  and  Ligaments  of  the  Foot 564 

The  Ligamentous  Support  of  the  Arch 

of  the  Foot 566 

Muscles  of  the  Foot 568 

Action  of  the  Muscles  in  Supporting 

the  Arch 568 

Action   of   the   Muscles   as    Flexors 

and  Extensors 569 

Action  of  the  Muscles  as  Abductors 

and  Adductors 570 

Surface  Anatomy  of  the  Foot 570 

Tendons  of  the  Foot 571 

Joints  of  the  Foot 572 

Arteries  of  the  Foot 572 

Amputations 574 

C'nopart's 575 

Lisfranc's 575 

Plantar  Abscess 575 

Deformities  of  the  Feet 576 

Talipes  Varus 576 

Talipes  Valgus 577 

Flat  Foot 577 

Talipes  Equinus 578 

Talipes  Calcaneus 578 

Talipes  Cavus 578 

Hallux  Valgus 579 

The  Toes 579 

Ingrown  Nail 579 

Hammer  Toe 579 

Luxation  of  the  Toes 580 

Metatarsalgia 5S0 

Resection  of  the  Metatarsophalan- 
geal Joint 580 

Amputation  of  the  Toes 581 


APPLIED  ANATOMY. 


THE  SCALP. 

The  scalp  is  formed  by  the  movable  soft  tissues  which  cover  the  skull.  It  is 
composed  of  three  layers:  skin,  superficial  fascia,  and  occipitofrontalis  iimscle  \\it\\ 
its  aponeurosis.  It  is  attached  to  the  underlying  pericranium  by  loose  connective 
tissue  called  the  subaponeurotic  layer.  The  pericranium,  or  periosteum  of  the  skull, 
is  loosely  attached  to  the  bones  by  a  small  quantity  of  connective-tissue  fibres  called 


Epicranial  aponeurosis 

Superficial  fascia 

Skin 


\  \  //  r 


Fig  i.^Thescalp. 

by  some  anatomists  the  subpericranial  connective  tissue.  At  the  sutures,  however,  it 
is  very  firmly  attached. 

The  principal  affections  of  the  scalp  are  wounds,  inflammation,  affections  of 
the  blood-vessels,  tumors,  and  neuralgia.  The  peculiarities  of  these  affections  are 
determined  by  the  anatomical  structure  of  the  parts. 

The  skin  of  the  scalp  is  probably  the  thickest  in  the  body,  although  not  so 
dense  as  that  of  the  heel.  Besides  the  hair,  it  contains  abundant  sweat  and  sebaceous 
glands.  These  latter  are  connected  with  the  hair-follicles  and  are  near  the  surface. 
The  skin  increases  in  thickness  from  the  frontal  to  the  occipital  region. 

The  superficial  fascia  consists  of  a  net-work  of  connective-tissue  fibres  which 
run  from  the  skin  above  to  the  aponeurosis  of  the  occipitofrontalis  below.  In  its 
meshes  are  fat,  blood-vessels,  nerves,  and  lymphatics.  The  hair-bulbs  often  pierce 
the  skin  and  e.xtend  into  this  layer. 

The  fibres  of  the  superficial  fascia  bind  the  skin  so  firmly  to  the  aponeurosis 
beneath  that  when  the  skin  is  moved  the  aponeurotic  layer  is  carried  with  it.      The 


2  APPLIED    ANATOMY. 

arrangement  of  the  fibres  is  shown  in  Fig.  3.  Fibres  starting  from  the  point  A  not 
only  pass  directly  down  to  B,  but  also  to  each  side  to  the  points  Cand  /?.  In  the 
same  way,  fibres  starting  from  B  not  only  pass  upward  to  .-J,  but  also  forward  to  £ 
and  backward  to  -F.  Now,  if  the  skin  is  moved  in  the  direction  of  the  forward  arrow, 
the  fibres  £  B  and  A  D  are  tightened  and  drag  the  aponeurosis  forward.  If  the  skin 
is  moved  in  the  direction  of  the  backward  arrow,  the  fibres  A  C  and  F B  are  tight- 
ened and  so  drag  the  aponeurosis  backward.  Thus  it  is  seen  that  the  aponeurosis 
must  follow  the  movements  of  the  skin. 

The  occipitofrontalis  muscle  with  its  aponeurosis  arises  from  the  supe- 
rior curved  line  of  the  occiput  and  is  inserted  into  the  skin  of  the  frontal  region. 


Merkel  describes  the  epicranial  aponeurosis  as  dividing  into  two  layers,  one  inserting 
into  the  skin  and  the  other  into  the  rim  of  the  orbit  {Hand,  der  top.  Anat.  Bd.  i,  p. 
17).  _  The  bellies  of  the  muscle  are  comparatively  short,  about  5  cm.  in  length,  the 
remaining  tissue  extending  between  them  constituting  the  aponeurosis.  As  it  comes 
downward  from  the  temporal  ridge,  over  the 
sides  of  the  head,  the  aponeurosis  becomes 
thinner  and  gives  attachment  by  its  superficial 
surface  to  the  anterior  and  superior  ajiriadar 
muscles.  It  then  proceeds  downward  to  be 
attached  to  the  upper  edge  of  the  zygoma. 


Fig.  3.— Diagram  illustrating  the  method  of  attach- 
ment of  theskin  to  the  aponeurosis  of  the  occipitofrontalis 
muscle. 


Fig.  4. — Showing  now  the  periosteun 
childhood  dips  between  the  bones  in  tlie  lii 
the  sutures. 


Contraction  of  the  occipitofrontalis  muscle  causes  the  skin  of  the  forehead  to  wrinkle 
transversely.  It  is  a  muscle  of  expression,  and  blends  with  the  pyramidalis  nasi 
and  comigator  sitpcrcilii.      It  is  supplied  by  branches  of  the  facial  ner\'e. 

The  subaponeurotic  tissue  is  very  loose  and  abundant,  so  that  it  does  not  tend 
to  confine  the  movements  of  the  scalp,  but  favors  them.  Hence  the  scalp  is  readily 
torn  loose  from  the  skull  in  scalping,  machinery  accidents,  etc.  This  tissue  is  so 
loose  that  effusions  accumulate  here  and  spread  extensively.  It  contains  only  a  few 
blood-vessels. 

The  pericranium  in  its  normal  condition  is  a  thin,  tough  membrane  containing 
few  blood-vessels.  Except  at  the  sutures,  where  it  is  firmly  attached  and  dips 
down  between   the  bones,   it  is   comparatively  easily  stripped  from   the  skull  and 


THE    SCALP.  3 

does  not  convey  much  nourishment  to  it.  It  is  deficient  in  osteogenetic  oi  bone- 
forming  properties,  so  that  when  it  is  raised  off  the  skull  in  operations,  and  the 
bone  removed  from  beneath,  as  occurs  in  trephining,  fractures,  etc. ,.  new  bone  is  not 
produced. 

The  subpericranial  tissue  is  so  scanty  and  loose,  particularly  in  infancy,  that 
it  readily  allows  the  pericranium  to  be  raised  and  effusions  to  occur  beneath. 


THE  ARTERIES   OF  THE  SCALP. 

The   scalp    is  supplied    by  the   frontal,  supra-orbital,   and  sometimes  a   small 
branch  from  the  lachrymal  arteries,  from  the  ophthalmic;  by  the  temporal,  through 


Supra-orbital 
Frontal 


its  anterior  and  posterior  branches ;  and  by  the  posterior  auricular  and  the  occipital 
arteries  from  the  external  carotid.  These  arteries  communicate  freely  with  each 
other,  not  only  laterally,  but  also  across  the  top  of  the  scalp.  It  is  not  unusual  to 
see  a  large  branch  of  the  temporal  communicating  directly  with  the  occipital. 

The  temporal  artery  begins  in  the  substance  of  \\\&  parotid  gland ,  just  below 
the  condyle  of  the  jaw,  and  mounts  over  the  zygoma,  a  centimetre  (or  less)  in  front 
of  the  ear.  It  lies  on  the  temporal  fascia  and  its  pulsations  can  be  felt  at  this  point, 
if  desired,  during  the  administration  of  an  anaesthetic.  About  four  centimetres  ( i  ^2 
in. )  above  the  zygoma,  it  divides  into  the  anterior  and  posterior  branches.  The 
auriculotemporal  branch  of  the  fifth  nerve  lies  just  in  front  of  the  ear  and  between  it 
and  the  temporal  arterv. 

The  occipital  artery  mounts  to  the  scalp  in  the  interval  between  the  pos- 
terior border  of  the  sternomastoid  muscle  and  the  anterior  border  of  the  trapezius. 
It  is  about  midway  between  the  posterior  border  of  the  mastoid  process  and  the 
occipital  protuberance.     If  it  is   desired  to   expose  it  from  this  point  forward,  the 


4 


APPLIED    ANATOMY. 


sternomastoid,  splenius  capitis,  and  trachelomastoid  muscles  will  have  to  be  cut, 
because  it  passes  beneath  them.  The  occipitalis  major  nerve  lies  to  the  inner  side  of 
the  artery. 

Occipital  arterj'  ^  ^       g  _  Superior  oblique 

'  Sternomastoid 
Trachelomastoid 


Fig.  6. — Occipital  arte 


LYMPHATICS  OF  THE  SCALP. 

The  lymphatics  anteriorly  near  the  median  line  pass  down  between  the  orbits  to 
reach  the  submaxillar)'  nodes.  Those  of  the  anterior  parietal  and  temporal  regions 
empty  into  the  pre-auricular  nodes;  those  of  the  posterior  parietal  and  temporal, 
into  the  nodes  behind  and  below  the  ear;  and  those  of  the  occipital  region  into  the 
occipital  nodes.  Infectious  troubles  of  these  regions,  therefore,  will  cause  enlarge- 
ment of  the  corresponding  nodes. 

AFFECTIONS  IN\'OLMNG  THE  LAYERS  OF  THE  SCALP. 

Wounds  of  the  scalp  are  common.  Incised  wounds  bleed  more  freely  and  the 
hemorrhage  is  more  difficult  to  control  than  in  wounds  elsewhere  on  the  surface. 
This  is  due  to  the  exceedingly  free  blood  supply  and  to  the  peculiar  arrangement  of 
the  blood-vessels  in  the  tissues. 

Small  wounds  of  the  scalp  do  not  gape,  particularly  if  they  are  longitudinal  in 
direction  and  not  very  deep.  The  skin  is  so  intimately  bound  to  the  aponeurosis 
beneath  that  displacement  is  impossible.  If  the  cut  is  deep  enough  to  divide  the 
aponeurosis  extensivelv,  especiallv  if  the  wound  is  transverse,  gaping  is  marked. 
This  is  produced  bv  contraction  of  the  two  bellies  of  the  occipitofrontalis  muscle, 
which  pulls  the  edges  apart. 

Bleeding  is  apt  to  be  persistent  and  hard  to  control  because  the  arteries  running 
in  the  deep  layers  of  the  skin  and  fibrous  trabeculae  are  firmly  attached  and,  there- 
fore, when  cut,  their  lumen  cannot  contract  nor  their  ends  retract.  When  large 
flaps  are  torn  in  the  scalp,  they  rarely  die  because  of  their  free  blood  supply,  and 
sloughing  is  limited  to  the  parts  which  are  actually  contused.  As  the  subaponeur- 
otic space  is  often  opened,  if  the  wound  is  sewed  too  tightly  shut,  subsequent  bleeding 
instead  of  escaping  externally  may  extend  widely  under  the  aponeurosis.  Inasmuch 
as  hair  and  dirt  are  often  crushed  into  these  wounds,  great  care  should  be  taken  to 


THE   SCALP. 


disinfect  them.  A  cut  will  open  the  hair  bulbs  and  sebaceous  glands,  and,  as  the  hairs 
project  into  the  subcutaneous  tissue,  they  may  serve  as  a  starting  point  for  infection. 

Contraction  of  the  occipitofrontalis  muscle  may  prevent  healing  in  e.xtensive 
wounds.     To  avoid  this  the  scalp  is  co\'ered  by  a  recurrent  bandage  or  otherivise  fixed. 

Lacerated  wounds  do  not  bleed  so  freely  as  do  incised  wounds,  but  they  are 
accompanied  by  a  more  extensive  loosening  of  the  scalp.  Large  flaps  of  tissue  are 
frequently  raised  and  turned  to  one  side.  The  most  severe  of  these  injuries  have  been 
produced  by  the  hair  being  caught  by  a  revolving  shaft,  tearing  nearly  the  whole 
scalp  oS.  Its  loose  attachment  to  the  pericranium  and  bone  beneath  by  the  loose 
subaponeurotic  tissue,  readily  explains  the  reason  of  these  extensive  detachments. 

Coiitusioiis  cause  only  a  moderate  amount  of  swelling,  which  is  usually  circum- 
scribed. While  the  skin  is  not  broken,  the  blood-vessels  and  other  tissues  beneath 
are  often  ruptured,  and,  therefore,  extravasation  of  blood  occurs.  When  this  is  con- 
fined to  the  superficial  fascia,  it  is  small  in  amount  and  limited  in  area.  It  does  not 
tend  to  work  its  way  for  any  great  distance  beneath  the  skin.  If  the  extravasation 
extends  below  the  aponeurosis,  it  may  cover  a  considerable  area  of  the  skull.  When 
it  occurs  beneath  the  pericranium  it  is  called  cephalhematoma,  or  in  the  new-born 
caput  succedaneum.  Caput  succedaneum  is  found  almost  always  on  the  right  side, 
involving  the  parietal  eminence.  It  is  limited 
by  the  attachment  of  the  pericranium  at  the 
sutures. 

HcEmatomas  of  the  scalp  possess  the  pecu- 
liarity of  being  soft  in  the  centre  and  sur- 
rounded by  a  hard  cedematous  ring  of  tissue. 
In  cephalhsematoma  of  long  standing  this  ring 
may  ossify,  and  the  new  bone  may  even  extend 
and  form  a  more  or  less  perfect  bony  cyst. 
This,  however,  is  very  rare. 

Heematomas  produced  by  blows  on  the 
head  are  often  mistaken  for  fractures.  The 
raised  edge  is  so  hard  as  sometimes  to  be 
thought  to  be  the  edge  of  broken  bone.  The  tis- 
sues beneath  the  skin  at  the   site  of  impact 

seem  to  be  pulpified  and  remain  perfectly  soft  to  the  touch;  the  smooth  unbroken 
skull  can  usually  be  felt  over  an  area  equal  to  the  site  of  impact.  Surrounding  this 
soft  area  is  the  hardened  ring,  composed  of  tissues  between  the  skin  and  the  bone, 
into  which  serum  and  blood  have  been  effused. 

Inflammation  and  abscess  are  caused  by  infected  wounds,  furuncles,  erysipelas, 
caries  of  the  skull  and  suppurating  sebaceous  cysts. 

The  scalp  is  a  favorite  location  for  erysipelas;  if  not  started  primarily  by  an 
infected  wound,  the  scalp  may  be  involved  secondarily  by  extension  from  the  face. 

Caries  of  the  skull  is  often  of  syphilitic  origin. 

Abscesses  may  occur  in  three  places: 

1 .  Subcutaneous. 

2.  Subaponeurotic. 

3.  Subpericranial. 

I.  Subcutaneous  abscesses  are  usually  small  and  do  not  tend  to  spread  but 
rather  to  discharge  through  the  skin.  This  is  because  the  firm  fibrous  trabeculae 
prevent  lateral  extension.  Furuncles  are  quite  common  in  childhood;  they  are,  of 
course,  superficial  to  the  aponeurosis.  Sebaceous  cysts  are  especially  common  in 
the  scalp  and  they  sometimes  suppurate.  The  orifi:ce  of  the  obstructed  duct  is  not 
usually  visible.  Sometimes  in  a  small  cyst  a  black  spot  on  its  surface  indicates 
the  opening  of  the  duct.  By  means  of  a  needle  or  pin  this  opening  can  be  dilated 
and  some  of  the  contents  expressed.  Of  course,  if  nothing  further  is  done  it  will 
reaccumulate.  When  these  cysts  become  inflamed  they  become  united  to  the  skin 
above  so  that  it  has  to  be  dissected  off.  If  pus  forms,  it  either  remains  localized  to 
the  cyst  or  bursts  through  the  skin  and  dischaiges  externally.  It  does  not  tend 
to  burrow  under  the  skin  laterally  on  account  of  the  fibrous  trabeculae  tmiting  the 


-Hsematoma  011  the  forehead  of  a  child. 


APPLIED    ANATOMY. 


skin  and  aponeurosis.  The  aponeurosis  beneath  is  intact,  therefore  the  pus  does 
not  get  below  it.  The  cyst,  with  the  hning  membrane  entire,  sliould  be  removed, 
otherwise  it  will  recur. 

2.  Subaponeurotic  abscesses  come  h'om  infected  wounds,  erysipelas,  or  caries  of 
the  bones.  It  is  not  desirable  to  close  deep  wounds  of  the  scalp  too  tightly.  Some 
suppuration  is  liable  to  occur  which,  not  finding  an  easy  escape  externally,  may 
spread  under  the  aponeurosis  if  the  wound  has  been  deep  enough  to  divide  it. 
Infection  of  wounds  is  the  most  frequent  source  of  these  abscesses,  hence  the  desira- 
bility of  providing  for  drainage  for  at  least  a  short  period.      In  erysipelas,  serous 

efTusion,  which  may  become  purulent,  oc- 
cuis  in  the  subaponeurotic  tissue,  as  well  as 
1  1  the  laj'ers  above.  It  may  sink  down- 
waid  and  point  in  the  temporal,  occipital,  or 
fiontal  region.  In  the  temporal  region  the 
descent  of  the  pus  may  be  limited  by  the 
attachment  of  the  lateral  e.\pansion  of  the 
auoneurosis  to  the  zygoma.  The  attachment 
ot  the  occipitalis  muscle  posteriorly  to  the 
superior  curved  line  of  the  occiput  prevents 
the  effusion  from  coming  to  the  surface  at 
that  point.  The  liquid  accumulates  low  down 
on  the  forehead  over  the  orbits,  being  pre- 
\ented  from  entering  by  the  attachment  of 
the  orbitotarsal  ligament,  and  tends  to  point 
close  to  the  median  line.  The  frontal  muscles 
of  the  two  sides  are  apt  to  be  slightly  sep- 
aiated,  leaving  a  weak  spot  just  above  the 
loot  of  the  nose,  and  this  is  where  fluctua- 
tion can  most  easily  be  felt.  These  accumu- 
lations in  the  frontal,  temporal,  and  occipital 
regions  may  require  incisions  for  their  evac- 
uation and  drainage.  Suppuration  arising 
from  "carious  bone  readily  perforates  the 
pericranium  and  then  infiltrates  the  loose 
subaponeurotic  tissue.  The  bones  of  the  vault  of  the  skull  are  not  infrequently 
affected  by  syphilitic  disease,  producing  caries  and  suppuration,  which  invade  the 
subaponeurotic  space. 

3.  Subpericranial  abscesses  are  comparatively  rare.  They  usually  start  from 
diseased  bone  and  spread  laterally  beneath  the  pericranial  tissue.  The  pus  may  be 
limited  to  a  single  bone  on  account  of  the  firmer  attachment  of  the  pericranium  at  the 
site  of  the  sutures.  To  avoid  breaking  into  the  subaponeurotic  space,  a  free  opening 
should  be  made  into  the  abscess  so  as  to  allow  the  pus  to  drain  externally. 


Fig.  8. — Arterial  angioma  or 


AFFECTIONS    OF   THE    BLOOD-VESSELS. 

The  arteries  or  veins  alone  may  be  affected,  or  both  may  be  in\'olved. 

Arterial  varix  is  the  name  given  to  an  enlargement  of  a  single  artery.  It  forms 
a  swollen,  tortuous,  pulsating  mass  in  the  course  of  the  artery.  The  temporal  artery 
is  liable  to  be  so  affected,  particularly  its  anterior  branch. 

Cirsoid  aneurism,  or  aneurism  by  a.iastomosis,  is  formed  by  numerous  enlarged 
arteries.  It  is  sometimes  called  an  arterial  angioma  or plexifonn  angioma.  The 
veins  are  also  som2what  involved.      Pulsation  is  marked. 

Venous  angioma  is  a  tumor  formation  in  which  the  venous  blood  is  contained  in 
large  spaces,  which  are  lined  with  endothelium,  instead  of  in  normal  veins. 

Telangiectasis  or  nceviis  is  formed  of  enlarged  capillaries.  It  is  often  called 
port  wine  'mark,  mother's  mark,  etc. 

Aneurismal  varix,  or  arteriovenous  aneurism,  is  where  an  adjacent  artery  and 
vein  being  wounded, — as  the  temporal  artery  and  \'ein, — the  blood  passes  directly 
from  the  artery  into  the  vein. 


THE   SCALP.  7 

Varicose  aneurism  is  where  a  sac  intervenes  between  the  artery  and  vein,  so 
that  the  blood  passes  first  from  the  artery  into  the  sac  and  then  into  the  vein.  The 
temporal  artery  with  its  companion  vein  has  been  so  affected. 

Treatment  of  Vascular  Affections  of  the  Scalp. — Vascular  tumors  are 
usually  ligated  and  e.xcised.  Acupressure  pins  may  be  passed  under  the  larger 
arterial  trunks,  but  the  exceedingly  free  anastomosis  renders  thorough  excision 
preferable;  even  this  is  not  seldom  unsuccessful. 

TUMORS    OF   THE    SCALP. 

Sebaceous  cysts  arise  from  obstructed  sebaceous  glands;  the  contents  consists  of 
epithelial  cells,  fat,  and  cholesterin.  They  sometimes  calcify.  They  spread  in  the 
subcutaneous  tissue,  stretching  and  raising  the  skin  above  and  causing  atrophy  of 


the  hair  bulbs,  but  do  not  invoh-e  the  epicranial  aponeurosis  below.  In  removing 
them,  if  they  have  never  been  inflamed,  they  can  readily  be  turned  out  through  a 
slit  in  the  skin.  The  subaponeurotic  space  will  not  be  opened,  therefore  their 
removal  is  not  often  followed  by  bad  results. 

Enceplialocele  is  a  tumor  formed  by  a  protrusion,  through  the  skull,  of  the 
membranes  of  the  brain,  containing  brain  matter  and  cerebrospinal  fluid. 

Meningocele,  or  a  tumor  containing  the  meninges  of  the  brain  and  cerebrospinal 
fluid,  is  more  rare  in  the  skull  than  is  the  case  when  the  spine  is  affected.  It  pro- 
trudes through  an  unossified  part  of  the  skull,  and,  according  to  Sutton,  two-thirds  of 
the  cases  occur  in  the  occipital  region,  between  the  foramen  magnum  and  torcular 
Herophili.  He  characterizes  it  as  a  hydrocele  of  the  fourth  ventricle,  and  says  that 
nine  out  of  ten  cases  die  if  operated  on.  The  next  most  frequent  seat  for  meningo- 
cele is  at  the  root  of  the  nose  (Fig.  lo). 

Cephalhydrocele  is  the  name  given  to  a  pulsating  tumor  communicating  with  the 
interior  of  the  skull  through  a  traumatic  opening.     It  contains  cerebrospinal  fluid. 

Dermoid  tumors  occur  in  the  median  line  and,  according  to  Sutton,  are  most 
common  o\'er  the  anterior  fontanelle  and  external  occipital  protuberance.  They  often 
have  a  thin  pedicle  attaching  them  to  the  dura  mater  and  may  grow  either  inside  or  out- 
side the  skull.  They  are  formed  by  an  inclusion  of  some  of  the  tissue  of  the  ectoderm 
by  the  bones  as  they  approach  from  each  side  to  ossify  and  unite  in  the  median  line. 

A  congenital  tumor  located  at  the  root  of  the  nose  is  probably  an  enceplialocele; 
one  located  at  the  anterior  fontanelle  is  probably  a  dermoid;  a  tumor  in  the  occipital 
region  may  be  either,  but  a  dermoid  is  apt  to  be  higher  up  than  an  encephalocele. 


APPLIED    ANATOMY. 


THE  SKULL. 

The  skull  is  the  bony  framework  of  the  head.  It  is  divided  into  the  bones  of 
the  cranium  and  those  of  the  face.  The  hyoid  bone  is  usually  classified  with  the 
bones  of  the  head. 

The  cranium  consists  of  the  bones  forming  the  brain  case.  They  are  the 
occipital,  two  parietals,  the  frontal,  two  temporals,  the  sphenoid,  and  the  ethmoid. 

The  bones  of  the  face  are  fourteen  in  number,  there  being  two  single  bones 
and  six  pairs.  The  single  bones  are  the  mandible,  or  inferior  maxilla,  and  vomer ; 
the  pairs  are  the  superior  maxilla,  malar,  nasal,  palate,  lachrymal,  and  inferior 
turbijiated  bones. 

THE    SKULL    IN    CHILDHOOD. 

The  skull  of  the  infant  is  markedly  different  from  that  of  the  adult.  At  birth  the 
face  is  quite  small  and  undeveloped,  while  the  cranium  is  relatively  large.     The  frontal 

and  parietal  eminences  are  very  marked. 
The  vault  of  the  skull  is  not  entirely  os- 
sified and  the  sutures  are  not  completed. 
The  bones  of  the  base  of  the  skull 
originate  in  cartilage,  while  those  of  the 
vault  originate  in  membrane.  This  mem- 
brane has  one  or  more  centres  of  ossi- 
fication appearing  in  it  for  each  bone. 
These  centres  increase  in  size  and  finally 
meet  at  the  edges  of  the  bone,  thus  form- 
ing the  sutures.  At  the  time  of  birth  the 
sutures  are  represented  by  membrane, 
which  joins  the  adjacent  bony  edges. 

The  frontal  bone  has  two  centres  of 
ossification;  one  for  each  side.  These 
form  a  suture  in  the  median  line  of  the 
forehead  which  becomes  obliterated  in 
the  course  of  the  first  or  second  year. 
Traces  of  it  in  the  shape  of  a  groove  or 
ridge  can  sometimes  be  seen  or  felt  in  the 
adult  skull.  The  frontal  eminences  are 
far  more  marked  in  childhood  than  later 
in  life  and  give  to  children  the  promi- 
nent forehead  which  is  so  characteristic. 
A  similar  peculiarity  is  seen  in  the 
parietal  bones,  the  parietal  eminences 
being  quite  prominent.  On  this  account,  they  are  often  injured  in  childbirth, 
sometimes  being  compressed  by  the  obstetrical  forceps,  and  are  frequently  the  seat  of 
hcsmatonia  neonatorum.  The  cranial  bones  not  being  firmly  united  allow  of  a  certain 
amount  of  play  or  even  overlapping,  thus  facilitating  the  delivery  of  the  head  at  birth. 
Fontanelles. — At  the  juncture  of  the  various  bones  are  six  spaces  called  fontan- 
elles.  Two,  the  anterior  and  posterior,  are  in  the  median  line  of  the  cranium,  and 
four,  the  two  anterolateral  and  two  posterolateral,  are  at  the  sides.  The  fontanelles 
are  situated  at  the  four  corners  of  the  parietal  bones. 

The  anterior  fontanelle  is  the  largest.  It  is  diamond-shaped  and  formed  by  the 
frontal  suture  in  front,  the  interparietal  behind,  and  the  coronal  at  each  side.  It  is  usu- 
ally closed  by  the  end  of  the  second  year,  but  may  be  delayed  until  the  fourth.  In 
rickets  and  malnutrition  the  fontanelles  remain  open  longer  than  would  otherwise 
be  the  case. 

Th.e.  posterior  fontanelle  is  formed  by  the  juncture  of  the  parietal  (sagittal)  suture 
with  the  lambdoidal  suture.  It  is  triangular  in  shape  with  the  apex  forward  between 
the  two  parietal  bones,  the  sides  passing  down,  one  to  the  right  and  the  other  to  the 
left  of  the  top  of  the  occipital  bone. 


THE   SKULL. 


These  fontanelles  are  of  the  greatest  importance  in  diagnosing  the  position  of 
the  head  during  labor.  If  the  examining  finger  encounters  first  a  large  diamond- 
shaped  or  four-cornered  depression  with  its  anterior  angle  more  acute  than  the  pos- 
terior, the  accoucheur  will  know  that  it  is  the  anterior  fontanelle  which  is  presenting. 
By  following  one  of  the  sutures  backward  he  will  come  to  a  triangular  or  Y-shaped 
ridge  which  will  be  recognized  from  its  shape  as  being  the  posterior  fontanelle.  He 
will  then  know  that  the  position  of  the 
head  is  occipitoposterior.  If  the  posi- 
tion is  the  more  usual  occipito-anterior 
one,  the  finger  will  first  encounter  the 
posterior  fontanelle  with  its  three  sutures, 
which  are  distinctly  recognizable.  On 
following  the  suture  which  leads  back- 
ward, the  four-cornered  anterior  fon- 
tanelle will  be  felt.  The  various  sutures 
constituting  the  fontanelles  can  usually 
be  distinctly  felt,  and,  as  the  presenta- 
tions are  nearly  always  occipito-anterior, 
the  fontanelle  that  will  usually  be  first 
felt  will  be  the  posterior,  and  the  sutures 
forming  it  can  readily  be  counted. 

The  antcro-  3,r\A  posterolateral /o7i- 
tanelles,  located  at  the  anterior  and  pos- 
terior angles  of  the  parietal  bones,  are 
of  no  service  in  diagnosing  the  position 
of  the  head.    They  are  indistinct,  nearly 

closed,  and  thickly  covered  by  tissue.  In  injuries  to  the  skull  in  young  children 
and  infants,  we  should  not  mistake  the  fontanelles  and  lines  of  the  sutures  for 
fractures.  Fissures  e.xtending  into  the  occipital  bone  from  the  posterolateral  fonta- 
nelles are  normal  at  birth  and  not  due  to  injury. 

Dura  Mater. — The  dura  mater  in  children  is  more  firmly  attached  to  the 
interior  of  the  skull  than  in  adults.  If,  therefore,  a  true  fracture  does  occur,  lacera- 
tion of  the  dura  is  more 
liable  to  be  produced.  This 
firm  attachment  also  pre- 
vents the  formation  of  epi- 
dural hemorrhages,  because 
the  force  of  the  blow  is  not 
sufficient  to  loosen  the  dura 
from  the  bone,  and  when 
the  middle  meningeal  artery 
is  torn,  as  Marchant  has 
pointed  out,  the  bleeding 
is  more  apt  to  be  external 
than  internal. 

Cells  and  Air-sinuses. 
— The  infant  has  the  bones 
of  the  face  so  slightly  developed  that  there  is  no  room  for  the  cavities  which  after- 
ward develop  in  them.  The  ridges  of  the  bones  also  become  more  marked  as  age 
advances.      The  young  child  has  no  superciliary  ridges. 

The  maxillary  sums,  or  antrum  of  Highmore,  and  the  mastoid  antrum  are  the  only 
cavities  that  exist  at  birth.  They  are  both  much  smaller  than  they  ultimately  become. 
The  mastoid  antrum  in  relation  to  the  size  and  age  of  the  child  is  comparatively 
large,  being  about  five  milHmetres  in  diameter.  As  the  bone  in  the  child  is  unde- 
veloped, and  the  tympanum  lies  nearer  to  the  surface,  the  antrum  likewise  is  some- 
what higher  and  nearer  to  the  surface  than  is  the  case  in  adults.  This  should  be 
borne  in  mind  when  operating  on  the  bone  in  this  region  (Fig.  13). 

The  frontal,  ethmoidal,  and  sphetioidal  sinuses  appear  about  the  seventh  )'ear, 
but  it  is  not  until  puberty  is  reached  that  they  really  begin  to  develop.     The  mastoid 


auditory  meatus 


Mastoid  process 


Fig.  13. — The  surface  of  the  temporal  bone  has  been  chiselled  off, 
showing  the  relative  size  and  position  of  the  mastoid  antrum  and  external 
auditory  meatus. 


APPLIED   ANATOMY. 


cells  likewise  appear  at  pubert)-  and  increase  with  age.      At  birth,  they  are  repre- 
sented b\^  simple  cancellous  bone. 

THE  SKULL  IN  ADULTS. 

As  the  child  grows,  the  bones  of  the  face  increase  more  rapidly  than  do  those 

of  the  vault.      The  bony  prominences  become  marked,    due  to  the  action  of  the 

various  muscles  of  mastication,  expres- 
sion, etc.,  inserted  into  them.  The 
face  is  much  larger  in  size  in  proportion 
to  the  cah'arium  than  was  the  case  in 
infancy.  While  in  infancy  bone  is  prac- 
tically homogeneous,  in  late  childhood 
and  early  adult  life  cavities  begin  to 
develop  in  it. 

Outer  and  inner  tables  of  compact 
tissue  are  formed,  separated  by  diploic 
structure.  The  frontal,  ethmoidal,  and 
other  air-sinuses  are  an  exaggeration 
of  these  diploic  spaces.  They  are  lined 
with  mucous  membrane  and  communi- 
cate with  the  nasopharynx.  The  diploe 
first  begins  to  appear  about  the  age  of 

ten  years,  but  is  not  well  formed  until   early  adult  life.      It  contains  large  veins, 

called  the  diploic  veins,  which  communicate  with  the  veins  both  of  the  inside  and 

outside  of  the  skull.     In  injuries  to  the  skull 

bleeding  from  these  veins  is  rarely  trouble- 
some and  usually  stops  spontaneously. 

The  skull  is  thinner  in  the  white  than 

in  the  negro  race.     It  is  thickest  over  the 

occipital    protuberance  and    mastoid    proc- 
esses.    The  bone  is  thinnest  in  the  temporal 

and  lower  occipital  regions.     The  two  tables 

are  separated  widely  from   one  another  in 

the  region  of  the  frontal  sinuses. 

Tables. — The  inner  table  is  thinner  and 

more  brittle  than  the  outer  one,  and  in  frac- 
tures it  is  almost  always  more  extensively 

splintered  than  the  outer.     In  rare  cases  the 

outer  table  may  be  temporarily  depressed  by 

a  glancing  blow  and  spring  back  into  place 

without  showing  any  depression,  while  the 

inner  table  may  be  fractured. 

The  two  tables  are  not  exactly  parallel. 

Where  the  skull  is  thin,  as  in  the  temporal 

and    occipital    regions,    they   are    close    to- 
gether; where  it  is  thick,   they  are  farther 

apart.      The    outer    surface  of   the   skull  is 

comparatively  even  and  smooth.     The  inner 
•  surface  is  quite  uneven,  being  depressed  in 

places    to    receive    the   convolutions   of  the 

brain.    For  this  reason  it  is  necessary  to  use 

the  trephine  with   great  care,  as  it  ina}'  cut 

through  on  one  side  of  the  circle  and  injure 

the  dura  mater  before  it  cuts  through   the 

other  part. 

The  sutures  of  the  skull  begin  to  ossify 

at  about  the  age  of  forty  years  and  continue  to  fuse  until  about  the  eightieth  year. 
Frontal   Sinuses. — The  frontal  sinuses  begin  to  develop  at  the  age  of  seven 

years,  but  do  not  increase  rapidly  in  size  until  puberty.      When  adult  age  is  reached 


Frontal  sinus  of  one  side;  the  anterior  wall 
3een  cut  away,  exposing  its  interior. 


THE   SKULL.  ii 

they  are  well  developed.  They  may  extend  well  out  over  the  orbits,  reaching  to 
within  a  short  distance  of  the  temporal  ridge,  while  in  other  instances  they  do  not  go 
beyond  the  supra-orbital  notches.  In  height  they  may  reach  the  lower  portion  of 
the  frontal  eminences  or  may  cease  at  the  level  of  the  superciliary  ridges.  The  size 
of  the  sinus  cannot  be  judged  from  the  size  of  the  bony  prominences.     Neither  is  the 


Mastoid  antrum 

Sxiprameatal  spine 


Fig.  i6. — Surface  chipped  i 


Mastoid  cells 


■  to  show  the  mastoid  antr 


nd  cells,  the  latter  i 


ly  well  developed. 


size  nor  sex  of  the  individual  any  criterion.  In  a  small  female  we  have  seen  them  of 
considerable  size.  When  diseased  sufficiently  to  give  rise  to  symptoms,  they  will  be 
found  to  be  quite  large.  They  are  separated  from  each  other  by  a  septum,  and  if 
extensive  are  divided  into  several  pockets  or  recesses.     They  open  into  the  infundib- 


Superior  longitudinal  i 


ferior  longitudinal  ; 


Straignt  sinus 
Torcular  Herophil 


Lateral  sinus 
Occipital  sinus 

Superior  petrosal  ; 
Sigmoid  sinus 
Inferior  petr 


ulum,  at  the  anterior  extremity  of  the  middle  turbinated  bone  in  the  middle  meatus 
of  the  nose.  Fracture  of  the  outer  wall  of  the  sinus  not  infrequently  occurs  without 
involving  the  inner  table. 

Mastoid  Process. — The  mastoid  process  is  continous  with  the  superior  curved 
line  of  the  occiput.  It  increases  in  size  from  the  time  of  birth,  but  is  composed  of 
cancellous  tissue  until  after  the  age  of  puberty,  when  the  mastoid  cells  develop.  The 
mastoid  antrum,  a  cavity  five  millimetres  in  size  at  birth,  which  opens  into  the  upper 
posterior  portion  of  the  tympanum,  is  relatively  larger  at  birth  than  in  the  adult. 


12  APPLIED   ANATOMY. 

It  is  of  importance  in  ojjerating  for  infection  arising  from  middle-ear  disease.  Minute 
veins  run  from  the  antrum  into  the  lateral  sinus. 

Suprameatal  Triangle. — This  triangle,  so  named  by  Macewen,  is  formed 
above  by  the  posterior  root  of  the  zygoma,  anteriorly  by  the  bony  posterior  wall  of 
the  external  auditory  meatus  and  posteriorly  by  a  line  from  the  floor  of  the  meatus 
passing  upward  and  backward  to  meet  the  first  line.  The  mastoid  antrum  is  reached 
by  operating  through  this  triangle  (see  section  on  Ear). 

Cerebral  Venous  Sinuses. — ^^The  fibrous  membrane  which  lines  the  inte- 
rior of  the  skull  is  composed  of  two  layers  which  are  in  most  places  intimately 
united,  forming  one  single  membrane  known  as  the  dura  mater.  The  outer 
layer  is  applied  to  the  bone,  while  the  inner  layer  covers  the  brain.  In  certain 
places  these  two  layers  separate  to  form  channels  in  which  venous  blood  flows-; 
these  channels  are  called  sinuses.  In  certain  other  places  these  layers  separate  and 
enclose  some  special  structure,  as  the  Gassei-ian  ganglion. 

The  cerebral  sinuses  of  most  importance  are  the  superioi-  longitudinal,  the  latei'al 
or  transverse,  and  the  cavernous. 

The  superior  longitudinal  sinus  runs  in  the  median  line  from  the  foramen  csecum 
in  the  ethmoid  bone  in  front,  to  the  torcular  Herophili  behind.      As  it  passes  back- 


iid  torcular  He 


ward  it  inclines  more  to  the  right  side,  so  that  at  the  torcular  Herophili  the  left  side 
of  the  sinus  is  about  in  the  median  line.  This  sinus  receives  the  veins  from  the 
cortex  of  the  brain  and  also  some  from  the  diploe  of  the  bones  above  it.  A  vein 
pierces  the  upper  posterior  angle  of  each  parietal  bone  and  forms  a  communication 
between  the  superficial  veins  of  the  scalp  outside  and  the  superior  longitudinal  sinus 
within.  The  deviation  of  the  superior  longitudinal  sinus  toward  the  right,  as  it 
proceeds  posteriorly,  is  to  be  borne  in  mind  in  operating  in  this  region,  as  one  can 
approach  the  median  line  nearer  on  the  left  side  posteriorly  than  the  right,  without 
wounding  it.  In  the  parietal  region  the  Pacchionian  bodies  are  surrounded  by 
extensions  from  the  longitudinal  sinus  and  free  hemorrhage  will  ensue  if  the  bone  is 
removed  too  close  to  the  median  line. 

The  torcular  Herophili,  or  confluence  of  the  sinuses,  does  not  correspond  exactly 
to  the  external  occipital  protuberance  or  inion  on  the  exterior  of  the  skull.  It  is 
a  little  above  and  to  the  right  of  it.  This  torcular  Herophili  is  formed  by  the  meet- 
ing of  the  longitudinal  sinus  from  above,  the  lateral,  or  transverse  sinuses  from 
the  sides,  the  straight  sinus  from  in  front  and  the  occipital  sinus  from  below. 

The  lateral  or  transverse  sinuses,  of  which  there  are  two,  pass  from  the  torcular 
Herophili  toward  each  side  in  the  tentorium  between  the  cerebrum  and  cerebellum, 
following  the  superior  curved  line  of  the  occiput  until  just  above  the  upper  posterior 
portion  of  the  mastoid  process.     They  then  bend  downward  to  within  a  centimetre  of 


THE   SKULL. 


13 


the  tip  of  the  process  and  again  curve  forward  to  end  in  the  jugular  foramen  and  be 
continued  as  the  internal  jugular  vein.  The  S-shaped  curve  which  they  make  in  this 
part  of  their  course  has  given  rise  to  the  name  sigijioid  sinus.  In  its  course  along 
the  superior  curved  line  the  sinus  rises  abo\'e  the  level  of  a  line  drawn  from  the  inion 
to  the  centre  of  the  external  auditory  meatus. 

In  operating  for  cerebellar  abscess,  care  should  be  taken  to  place  the  trephine 
opening  sufficiently  low  down  to  avoid  wounding  this  sinus.  It  is  in  great  danger  of 
being  wounded  in  operating  for  septic  conditions  involving  the  mastoid  antrum  and 
cells.  Its  distance  from  the  surface  of  the  skull  varies  in  different  individuals,  and  it 
gets  farther  from  it  as  it  descends  to  the  level  of  the  tip  of  the  mastoid  process.      It 


Inferior  petrosril 


Srd— oc  lo    otor 


4tl  — t      \  lear  (pntUetic 


1  re  It 
tl  —fa      1 
Stl  -a    1  tory 
Qt]  —  lossopliaryngeal 

th—  atusdjneimiogastric) 
1  tl  — S!  nal  accessory 


tl  — 1  >pot,lossal 


Superior  longitudiDal  sinus 
Fig.  19. — E.xit  of  cranial 


s  at  the  base  of  the  skull. 


receives  the  blood  from  the  posterior  lower  portion  of  the  cerebrum  and  upper 
portion  of  the  cerebellum,  and  communicates  with  the  veins  outside  the  skull  through 
the  mastoid  and  posterior  condyloid  foramina. 

Running  along  the  upper  posterior  edge  of  the  petrous  portion  of  the  temporal 
bone,  in  the  attachment  of  the  tentorium,  is  the  superior  petrosal  sinus.  It  connects 
the  lateral  or  trans\'erse  sinus  about  its  middle  with  the  cavernous  sinus.  More 
deeply  situated,  and  running  from  the  cavernous  sinus  to  the  lateral  sinus,  just  as  it 
enters  the  jugular  foramen,  is  the  inferior  petrosal  sinus. 

The  petrosal  and  lateral  sinuses"  are  frequendy  torn  in  fractures  of  the  skull.  A 
fracture  passing  through  the  petrous  portion  of  the  temporal  bone  may  tear  the 
petrosal  sinuses,  and  hemorrhage  from  the  ear  might  come  from  this  source.  A 
fracture  through  the  posterior  cerebral  fossa  may  tear  the  lateral  sinus.  Leeches 
are  sometimes  applied  behind  the  ear  in  inflammadon  of  the  brain,  with  the  idea  of 
drawing  blood  from  the  lateral  sinus  through  the  mastoid  vein. 

The  occipital  sinus  is  usually  small  and  brings  the  blood  up  from  the  region  of 
the  foramen  magnum  to  the  torcular  Herophili. 

The  straight  sinus  runs  along  the  line  of  juncture  of  the  tentorium  and  falx 
cerebri.      It  receives  the  blood  from  the  ventricles  of  the  brain  which  are  drained  by 


14  APPLIED    ANATOMY. 

the  veins  of  Galen,  and  the  blood  from  the  falx  through  the  inferior  longitudinal 
situis.  This  latter  is  usually  very  small  and  sometimes  almost  lacking,  the  blood  in 
that  case  passing  upward  to  empty  into  the  superior  longitudinal  sinus. 

The  cavernous  sinus, — one  on  each  side, — is  a  large,  irregular  space  on  the  side 
of  the  body  of  the  sphenoid  bone.  It  runs  from  the  sphenoidal  fissure  in  front  to 
the  ape.x  of  the  petrous  portion  of  the  temporal  bone  behind.  In  front  it  is  continu- 
ous with  the  ophthalmic  vein,  and  receives  the  spl/enoparielal  siuus  which  brings  the 
blood  from  the  diploe  ;  behind  it  communicates  with  the  superior  and  inferior  petrosal 
sinuses.  The  two  sinuses  communicate  across  the  median  line  around  the  pituitary 
body,  forming  the  circular  si/ius,  and  across  the  basilar  process,  forming  what  is 
sometimes  called  the  transverse  sinus,  but  which  is  more  correctly  described  as  a 
plexus  of  \-eins. 

The  cavernous  sinus  has  embedded  in  its  outer  wall  the  third  and  fourth  nerves 
and  the  ophthalmic  branch  of  the  fifth.  Farther  below  and  to  the  outer  side  of  the 
sinus  are  the  superior  and  inferior  ma.xillary  or  mandibular  branches  of  the  fifth 


Ophthalmic  branch  of  5th  i 


Internal  carotid  artery 


nerve.  Within  the  sinus  and  toward  its  lower  and  inner  portion,  is  the  internal 
carotid  artery.  It  is  surrounded  by  the  blood-current.  Between  the  carotid  artery 
and  outer  wall  of  the  sinus  runs  the  sixth  nerve,  held  in  place  by  fine,  trabecular, 
fibrous  bands  which  pass  from  side  to  side  in  the  cavity  of  the  sinus. 

The  cavernous  sinuses  are  sometimes  torn  in  fractures  of  the  base  of  the 
skull,  resulting  in  a  traumatic  communication  between  the  carotid  artery  and  the 
sinus.  The  cavernous  sinus  is  not  infrequently  torn  in  attempting  the  removal 
of  the  Gasserian  ganglion,  particularly  if  its  ophthalmic  branch  is  attacked.  Its 
interior  is  not  one  large  cavity,  but  is  subdivided  by  fibrous  septa,  which  pass 
from  side  to  side.  It  is  sometimes  the  seat  of  thrombosis  and  infection,  which 
may  reach  it  through  the  ophthalmic  vein  in  front. 

FRACTURES    OF   THE    SKULL. 

Fractures  of  the  skull  are  almost  always  produced  by  violent  contact  of  the  skull 
with  some  solid  body.  In  some  cases  the  fracture  is  produced  by  a  blow  from  a 
moving  body,  as  when  a  person  is  struck  by  a  club.  In  others,  the  skull  is  moving 
and  strikes  a  body  at  rest,  as  when  a  person  falls  and  strikes  the  head  on  a  pave- 
ment. It  is  not  necessary  to  discuss  in  detail  the  mechanism  of  fractures  of  the  skull; 
it  is  sufificient  to  state  that  nearly  all  fractures  start  from  the  point  of  impact  and 
radiate  to  distant  regions.  The  effect  of  fracturing  blows  on  the  skull  of  a  child  is 
different  from  their  effect  on  the  skull  of  an  adult. 

Fractures  of  the  Skull  in  Children. — A  child's  skull  is  thin  and  weak,  and 
while,  to  a  certain  extent,  fragile  is  more  flexible  than  that  of  an  adult.  It  is  on  this 
account  that  blows  are  more  liable  to  expend  their  force  locally,  at  the  point  of  impact, 
and  not  produce  fractures  at  a  distance.  Therefore,  it  follows  that  fractures  of  the 
base  are  rare  in  children  in  comparison  with  fractures  of  the  vault.  Extensive 
fissured  fractures  are  also  rare.  A  blow  will  crush  the  skull  of  a  child  at  the  point 
of  impact,  much  as  an  egg-shell  is  broken  at  one  spot  by  hitting  it  with  a  knife 
handle.      A  marked   example   of  this  was    seen   in   the  case  of  a  small   boy  who, 


THE    SKULL.  15 

while  playing,  was  struck  by  a  baseball  on  the  left  frontal  eminence.  A  distinct 
circular  depression  or  cup  was  produced  exactly  corresponding  to  the  shape  of  the 
ball.  There  were  no  symptoms  of  cerebral  concussion,  because  the  force  of  the 
blow  was  expended  on  the  bone  and  not  transmitted  to  the  brain  within.  As 
pointed  out  by  Mr.  Rickman  Godlee,  the  sutures  in  very  young  children  being  soft, 
the  transmission  of  the  force  from  one  bone  to  another  is  prevented. 

The  diploic  structure  of  the  skull  is  not  well  developed  until  adult  age,  therefore 
the  bone  is  homogeneous.  It  is  also  elastic,  and,  particularly  in  infants,  it  may  be 
dented  without  being  seriously  fractured;  these  dents  are  apt  to  disappear  and 
become  level  with  the  surrounding  bone  as  the  child  grows  older.  The  dura  mater  is 
more  adherent  in  children  and  fractures  are,  on  that  account,  more  liable  to  tear  it 
and  even  lacerate  the  brain  beneath. 

Fractures  of  the  Skull  in  Adults. — As  adult  life  is  reached  the  inner  and 
outer  tables  of  the  bones  become  separated,  leaving  the  space  between  to  be  filled 
by  the  diploic  tissue.  The  diploe  consists  of  cancellous  bone  in  the  meshes  of  which 
run  the  diploic  veins  and  capillaries.  Both  the  inner  and 
outer  tables  are  brittle,  but  the  inner  especially  so.  It  is 
also  harder  and  more  compact  than  the  outer  table.  On 
account  of  this  difference  we  find  in  cases  of  fracture  that 
the  inner  table  is  more  comminuted  than  the  outer,  so  that, 
while  the  outer  may  show  a  single  line  of  fracture,  the  inner 
table  immediately  beneath  may  be  broken  into  several  frag- 
ments. This  is  one  reason  why  trephining  is  so  frequently 
resorted  to. 

In  rare  cases  there  may  be   depression   of  the  inner 
table  with  none  of  the  outer.      A  case  of  this  kind  occurred 
during  our  Civil  War.     A  soldier,  while  looking  over  a  ram- 
part, was  struck  a  glancing  blow  by  a  bullet,  on  the  upper  anterior  portion  of  the 
skull.      The  outer  table  at  the  site  of  injury  was  not  at  all  depressed,  but  the  inner 
table  had  a  large  piece  broken  off,  which  injured  the  membranes. 

The  elasticity  of  the  skull  is  shown  in  cases  of  fracture  in  which  hairs  are  found 
imbedded  in  the  line  of  fracture.  Figure  21  is  from  such  a  case.  A  negro  was 
struck  on  the  head  by  a  falling  rock  and  an  extensive  longitudinal  fracture  was  pro- 
duced in  which  many  hairs  were  fastened.  About  a  centimetre  from  the  main  frac- 
ture was  a  small  fissure,  not  over  a  centimetre  long,  and  sprouting  up  out  of  it,  like 
bushes  from  the  bare  ground,  were  a  number  of  hairs.  In  such  cases  the  hairs  are 
carried  into  the  line  of  fracture  by  the  force  of  the  blow ;  the  elastic  bone  then  springs 
back  into  place  and  pinches  the  hairs,  thus  holding  them  in  place. 

The  bones  of  the  adult  skull  are  very  strong  and  firmly  fixed.  The  sutures 
begin  to  unite  at  the  age  of  forty  years  and  are  likely  to  have  disappeared  at  the  age 
of  seventy.  Even  in  young  adults  the  fibrous  tissue  between  the  bones  has  so  nearly 
disappeared  that  they  practically  act  in  transmitting  force  as  one  continuous  bone. 
For  these  reasons  slight  blows  do  not  cause  fractures.  It  takes  a  very  heavy  blow 
usually  to  cause  a  fracture  and  the  force  is  so  great  that  shock  or  concussion  of  the 
brain  with  disturbance  of  its  functions  is  a  common  symptom. 

The  force  of  the  blow  is  expended  first  at  the  point  of  impact,  and  if  a  fracture 
occurs  it  usually  starts  there.  From  that  point  it  radiates  to  other  portions  of  the 
skull,  so  that  fractures  of  the  vault  frequently  extend  to  the  base.  The  course 
pursued  by  the  fracture  has  been  formulated  into  a  law  by  Aran  ;  that  they  take  a 
straight  line  from  the  point  of  impact  on  the  vault  to  the  base  of  the  skull,  and  are 
not  deflected  by  the  sutures. 

Charles  Phelps  ("Traumatic  Injuries  of  the  Brain")  found  that  in  127  cases  of 
fracture  of  the  base  of  the  skull,  12  implicated  the  base  only.  So  that,  if  we  are  able 
to  say  that  there  is  a  fracture  of  the  base  of  the  skull,  there  are  over  10  chances  to 
one  of  its  extending  up  into  the  vault.  In  only  two  were  the  fractures  more  than  a 
slight  fissure  ;  so  that  in  a  marked" fracture  of  the  base  there  would  be  63  chances  to 
one  of  its  extending  into  the  vault.  Also,  from  Aran's  law,  we  see  that,  if  we  diag- 
nose a  fracture  through  the  middle  ear,  we  may  be  pretty  sure  that  the  force  was 
applied  directly  above,  and  be  led  to  trephine  accordingly. 


i6 


APPLIED    ANATOMY. 


A  man  fell  from  an  electric  light  pole  and  was  brought  to  the  hospital  with  bleed- 
ing from  the  ear  and  other  symptoms  of  fracture  of  the  skull.  He  became  wildly 
delirious,  and,  feeling  sure  that  the  fracture  of  the  base  was  an  extension  from  the 
vault,  although  no  depression  could  be  felt,  he  was  trephined  above  the  external 
auditory  meatus  and  a  large  epidural  effusion  of  blood  e\'acuated.  He  recovered 
and  resumed  his  work.  In  this  case,  as  soon  as  the  bone  was  exposed,  a  thin  line 
of  fracture  was  seen  running  down  to  the  base  in  the  region  of  the  external  ear. 

Fractures  by  Contrecoup  or  Counter  Stroke. —  Fractures  by  counter 
stroke  are  now  regarded  as  of  much  less  frequent  occurrence  than  formerl)'.  Charles 
Phelps  found  in  147  cases  of  fracture  of  the  base  of  the  skull  12  which  had  not 
extended  from  the  vault.  In  these,  the  force  had  been  applied  to  the  parietal  region 
in  six,  and  in  five  to  the  occiput;  most  of  the  resulting  fractures  were  in  the  region 


Anterior  cerebral  foSSi 


ForaiiieD  rotund 


Middle  cerebral  fos: 


Posterior  cerebral  fossa 


Orliital  plate  of  frontal 


Cribriform  plate  of  ethir 


Lesser  "ing  of  sphenoid 
Optic  foramen 
Anterior  clinoid  process 
Greater  win^  of  sphenoid 
Sella  turcica 


Foramen  spinosum 
Body  of  sphenoid 
Petrous  portion  of  tempore 
Ijody  of  occipital 

Internal  auditory  meatus 

Jugular  or  post,  lacerated 
foramen 


Fig.  22.— Interior  view  of  the  base  of  the  skull,  showing  the  parts  most  liable  to  be  involved  in  fractures. 


of  the  orbit.  Only  two  of  the  tweh'e  cases  were  serious  fractures,  the  remaining  ten 
being  slight  fissures,  which  produced  no  symptoms. 

Hemorrhage  in  Fractures  of  the  Skull. — Hemorrhage  is  a  frequent  and  most 
valuable  symptom  in  diagnosing  the  existence  of  fracture  and  in  determining  its  location. 

Fracture  through  the  anterior  cerebral  fossa  may  open  the  frontal,  ethmoidal,  or 
sphenoidal  cells  and  cause  bleeding  from  the  nose  and  mouth. 

A  fracture  through  the  roof  of  the  orbit  causes  bleeding  into  the  orbital  cavity ;  the 
blood  works  its  way  forward  and  makes  its  appearance  under  the  conjunctiva  of  the 
ball  of  the  eye.  Its  progress  forward  toward  the  lids  is  blocked  by  the  orbitotarsal 
ligaments,  and  it  therefore  works  its  way  downward  to  the  bulbar  conjunctiva,  under 
which  it  advances  to  the  edge  of  the  cornea.  The  ordinary  ecchymosis  of  the  lids  and 
cellular  tissue  around  the  eye  is  usually  due  to  a  rupture  of  the  vessels  of  the  subcuta- 
neous tissue  by  a  blow  from  the  outside,  and  not  to  a  fracture  of  the  base  of  the  skull. 


THE    SKULL. 


17 


Fracture  through  the  middle  cerebral  fossa  may  pass  through  the  body  of  the 
sphenoid  or  basilar  process  of  the  occipital  bone  and  cause  bleeding  into  the  mouth. 
It  may  also  cause  an  accumulation  of  blood  behind  the  posterior  wall  of  the  pharynx, 
pushing  it  forward.      When  it  passes  through  the  petrous  portion  of  the  temporal 


Anterior  brand 
piercing  the  bom 


Posterior  branch 


Fig.  23.— Middle  and  poster: 


lingeal  arteries  supplying  the  interior  of  the  skull. 


bone,  as  is  frequently  the  case,  it  may  involve  the  external  auditory  meatus  and 
bleeding  from  the  ear  will  result. 

Fractures  through  the  posterior  cerebral  fossa  may  cause  bleeding  into  the  struc- 
tures of  the  back  of  the  neck.      This  is  not  common. 

Middle  Meni)igeal  Hemor7'hage. — Bleeding  from  the  middle  meningeal  artery, 
epi-  or  extradural  hemorrhage,  occurs  in  those  fractures  which  pass  through  the  region 


paternal  angular  process 


Fig.  24.— Points  of  trephin 


The  course  of  the  artery  has  been 


of  the  pterion.  This  point  is  the  junction  of  the  coronal  and  sphenoparietal  sutures, 
about  4  cm.  ( i  J^  in. )  behind  and  slighdy  above  the  external  angular  process  of  the 
frontal  bone.  The  middle  meningeal  artery  comes  up  through  the  foramen  spinosum 
and  then  goes  forward,    upward,  and  outward  to  the  lower  anterior  angle  of  the 


i8 


APPLIED    ANATOMY. 


parietal  bone.  It  sends  branches  forward  to  the  frontal  region  and  backward  to  the 
parietal  and  temporal  regions.  During  two  to  three  centimetres  of  its  course,  at  the 
pterion,  it  passes  entirely  through  bone,  and  therefore  if  a  fracture  occurs  at  this 
point  it  must  of  necessity  tear  the  artery.  The  posterior  branches  are  not  regular  in 
their  course,  one  passing  backward,  low  down,  parallel  to  the  zygoma,  and  another 
higher  up  in  the  direction  of  the  parietal  eminence.  The  branches  of  the  meningeal 
artery  nourish  the  bone  as  well  as  the  dura,  therefore  if  the  dura  is  loosened  from 
the  bone  hemorrhage  from  these  branches  occurs.  The  most  frequent  site  of  middle 
meningeal  hemorrhage  is  in  the  region  of  the  pterion  or  temple. 

In  trephining  for  it,  the  centre  of  the  trephine  is  to  be  placed  on  an  average  of 
4  cm.  {1^4  in.)  behind  the  external  angular  process  of  the  frontal  bone,  and  on  a 
level  with  the  upper  edge  of  the  orbit  or  4.5  cm.  ( i  S/j;  in.)  above  the  zygoma.  If 
the  artery  is  not  sufficiently  exposed  more  bone  is  to  be  removed  by  the  rongeur 


jrd — oculomotoi 


4th — trochlear  (patlie 


gth — trigeminal  (trifada!) 

6th — abducent 

7th — facial 

8lh — auditory 

9th— glossopharynge.il 

lotii — vagus  (pneumogastrlc) 

nth — spinal  a 


12th — hypoglossal 


at  the  base  of  the  skull. 


forceps.  It  is  in  this  region  that  epidural  hemorrhages  are  apt  to  be  extensive, 
because  the  vessels  torn  are  the  largest;  but  epidural  hemorrhage  can  also  occur  in 
the  frontal  region  from  the  anterior  branches  and  in  the  parietal  from  the  posterior. 

Trephining  for  bleeding  from  the  posterior  branch  of  the  middle  meningeal 
artery  is  somewhat  uncertain.  In  some  cases  the  artery  runs  low  down,  about  2  cm. 
(4'5  in. )  above  the  zvgoma  and  parallel  to  it.  In  other  cases  it  runs  upward  and 
backward  toward  the  parietal  eminence.  The  trephine  may  be  placed  as  high  up 
as  for  the  anterior  branch  of  the  middle  meningeal  artery,  4.5  cm.  (i^-i  in.),  and 
5  cm.  (2  in.)  farther  back.  This  will  be  belou-  and  anterior  to  the  parietal  eminence 
and  about  midway  on  a  line  joining  the  parietal  eminence  and  external  auditory 
meatus.  After  the  button  of  iDone  has  been  removed,  additional  bone  may  be  cut 
away  with  the  rongeur  forceps  until  access  can  be  had  to  the  bleeding  point  (see 
page  23  for  a  case  of  rupture  without  fracture). 

Rupture  of  the  large  venous  sinuses  and  of  the  small  vessels  passing  bet\veen  the 
bone  and  dura  also  contribute  to  the  formation  of  the  clot.      Owing  to  the  firrrier 


THE    SKULL. 


19 


attachment  of  the  dura  mater  in  children,  the  meningeal  arteries  are  more  liable  to 
be  torn  and  cause  hemorrhage  than  is  the  case  in  adults.  For  the  same  reason  the 
blood  pressure  is  not  sufficient  to  dissect  the  dura  from  the  skull,  therefore  epidural 
clots  are  rare.  If  there  is  a  fracture,  blood  may  collect  beneath  the  scalp,  and  if  an 
external  wound  exists,  the  blood  will  find  an  exit  through  it. 

Bleeding  from  the  Venous  Sinuses. —  Bleeding  may  occur  from  the  sinuses  of  the 
base  as  well  as  from  those  of  the  vault.  In  severe  injuries  of  the  vault  detached  frag- 
ments frequently  penetrate  the  superior  longitudinal  and  lateral  sinuses.  In  these 
cases  profuse  bleeding  occurs  as  soon  as  attempts  are  made  to  remove  the  loose  pieces 
of  bone,  and  it  is  necessary  to  use  a  packing  of  gauze  to  control  it.  Fractures  passing 
through  the  petrous  portion  of  the  temporal  bone  wound  the  petrosal  sinus  and 
this  no  doubt  contributes  to  the  blood  which  flows  from  the  ear. 

Emphysema  is  most  likely  to  occur  if  the  frontal  air  sinuses  are  involved,  partic- 
ularly if  the  patient  blows  his  nose  in  the 
attempt  to  relieve  it  of  blood  clots.     Em- 
physema is  not  so  liable  to  occur  in  cases 
of  fracture  involving  the  mastoid  cells. 

Cerebrospinal  fluid  ma}^  escape  when- 
ever the  meninges  are  torn  and  the  sub- 
arachnoid space  is  opened.  It  is  most  fre- 
quently seen  in  the  fractures  in^•olving  the 
middle  fossa  and  passing  through  the  in- 
ternal auditory  meatus.  The  meninges  are 
prolonged  into  the  internal  meatus,  and  the 
clear  fluid  is  not  infrequently  seen  coming 
from  the  ear  of  the  injured  side.  Although 
the  normal  amount  of  cerebrospinal  fluid 
is  only  about  two  ounces,  much  greater 
quantities  can  escape.  A  serous  discharge, 
perhaps  of  several  ounces,  is  indicative  of 
a  rupture  into  the  subarachnoid  space. 

Injuries  to  Nerves  in  Fracture 
of  the  Skull. — The  nerves  most  often 
disturbed  in  injuries  of  the  skull  are  the 
first,  second,  third,  seventh,  and  eighth. 

The  first  or  olfactory  nerve  may  be 
injured  directly  in  the  line  of  fracture,  or 

by  concussion.  I  have  had  under  my  care  two  such  cases  in  \\'omen  who  struck  the 
occiput  on  an  asphalt  pavement  in  getting  off  backward  from  a  mo\-ing  trolley  car. 
These  patients  left  the  hospital  after  several  weeks  with  the  sense  of  smell  still  lacking. 

Injuries  to  the  second  or  optic  7ierve  are  apt  to  be  accompanied  by  such  severe 
injuries  to  other  parts  as  to  cause  the  death  of  the  patient  before  the  loss  of  sight  is 
discovered.  If  the  optic  nerve  is  injured  at  the  optic  foramen,  there  may  be  impair- 
ment of  sight  without  any  intra-ocular  changes  to  be  seen  with  the  ophthalmoscope. 
Inside  of  two  weeks,  however,  the  pinkish  color  of  the  disk  gives  way  to  the  gray- white 
color  of  atrophy,  and  this  progresses  until  complete.  The  nerve  ne\er  resumes  its 
functions  and  the  patient  remains  blind. 

Injury  of  the  third  or  oculomotor  nerve  has  also  come  imder  mv  notice.  In  this 
the  pupil  of  the  affected  eye  is  moderately  dilated  and  does  not  respond  to  light. 
The  ciliary  muscle  is  supplied  by  the  third  ner\'e,  as  well  as  the  circular  fibres  of  the 
iris,  so  that  the  accommodation  is  paralyzed  and,  if  the  eye  has  been  normal  in  its 
refraction,  the  patient  will  be  unable  to  read  or  see  objects  clearly  at  close  distances. 
The  extrinsic  muscles  of  the  eye,  with  the  exception  of  the  superior  oblique  and 
external  rectus,  are  also  supplied  by  this  nerve  and  the  eye  is  therefore  pulled  outward 
and  slightly  downward,  and  diplopia,  or  double  vision,  may  be  produced.  The  patient 
is  unable  to  mo\e  the  eye  either  upward,  inward,  or  downward.  The  levator  palpe- 
brce  muscle  is  also  paralyzed  and  there  is  ptosis  or  drooping  of  the  upper  lid.  The 
orbicularis  palpebrarum  muscle,  being  supplied  by  the  seventh  nerve,  has  its  frmc- 
tions  unimpaired,  and  the  eyelids  can  be  closed. 


20  APPLIED   ANATOMY. 

The  foiu'th  or  pathetic  7iei've  is  almost  never  injured.  It  supplies  the  superior 
oblique  muscle,  which  turns  the  eyeball  down  and  slightiy  outward.  Paralysis  of  it 
causes  diplopia,  with  the  image  of  the  injured  eye  below  that  of  the  sound  eye  and 
tilted  to  the  right,  if  the  right  eye  is  affected,  and  to  the  left,  if  the  left  is  affected. 

The  Jifth  or  trifacial  nerve  is  \-ery  rarely  injured.  If  it  is  complete!}'  paralyzed 
there  will  be  loss  of  motion  in  the  muscles  of  mastication  and  loss  of  sensation  over 
the  side  of  the  face,  of  one-half  of  the  interior  of  the  mouth,  of  the  side  and  front  of 
the  tongue,  and  of  the  eye. 

The  sixth  or  abducent  ne7-ve  supplies  the  external  rectus  muscle  of  the  eye,  and 
if  paralvzed  causes  internal  strabismus,  the  eye  looking  inward.  While  more  often 
paralvzed  than  the  fourth  and  fifth,  it  is  not  so  frequently  paralyzed  as  are  the  two 
following  nerves. 

The  seventh  or  facial  nerve  is  the  one  most  frequently  injured  in  fractures  of  the 
skull.  It  enters  the  internal  auditory  meatus  with  the  auditor}^  nerve,  being  above 
it.  Reaching  the  end  of  the  meatus  internus,  it  enters  the  canal  of  Fallopius  and 
emerges  from  the  temporal  bone  at  the  stylomastoid  foramen.  When  paralyzed,  the 
face  on  that  side  remains  motionless,  the  eye  cannot  be  closed,  and  food  accumulates 
between  the  teeth  and  cheek.  The  corner  of  the  mouth  is  drawn  to  the  opposite 
side  when  the  muscles  of  the  face  are  contracted. 

The  internal  auditory  meatus  contains  a  prolongation  of  the  dura  mater  and 
arachnoid,  so  that  a  fracture  through  it  would  open  the  subarachnoid  space  and  allow 
the  cerebrospinal  fluid  to  escape.  In  these  cases  there  is  also  usually  bleeding  from 
the  ear.  Escape  of  cerebrospinal  fluid  is  to  be  distinguished  from  a  flow  of  serum  bj' 
its  greater  quantity,  sometimes  many  ounces  escaping. 

The  eighth  or  auditory  nerve  is  injured  with  moderate  frequenc}',  but  perhaps 
hardly  so  often  as  supposed,  for  the  deafness  \\'hich  sometimes  follows  injuries  to  the 
head  may  not  be  caused  by  an  injury  to  the  auditory  nerve  itself,  but  is  rather  due  to 
the  injury  done  bv  concussion  of  the  brain  in  the  region  of  the  first  temporal  con- 
volution, or  possiblv  to  the  tympanum.  The  eighth  nerve  is  embraced  in  the  same 
e.xtension  of  the  meninges  into  the  internal  meatus  as  is  the  seventh,  and  injuries  to  it 
may  also  be  accompanied  with  loss  of  cerebrospinal  fluid.  The  se\'enth  and  eighth 
are  said  to  be  more  often  paralyzed  than  any  of  the  other  nerves. 

Injuries  to  the  remaining  four  ner\-es  — ■  the  glossopharyngeal ,  vagus,  spinal 
accessory,  and  hypoglossal — have  been  obser\-ed  too  rarely  to  require  any  extensive 
attention  here. 

THE  MENINGES. 

The  meninges  of  the  brain  consist  of  three  separate  coverings:  the  outer  being 
the  dura  viater,  the  middle  the  arachnoid,  and  the  inner  the  pia  mater. 

The  dura  mater  or  fibrous  covering  of  the  brain  is  tough  and  strong  and 
intended  to  protect  it.  Injuries  of  the  skull  without  a  laceration  of  this  membrane 
are  much  less  serious  than  when  it  is  in\'oh-ed.  W^hen  it  is  torn,  not  only  is  the 
brain  beneath  likely  to  be  injured,  but  an  opportunit\'  is  giv'en  for  infection  to  enter 
and  affect  the  brain  itself  and  even  produce  a  hernia  cerebri  or  hernial  protrusion  of 
brain  matter  through  the  rent. 

The  dura  mater  is  composed  of  two  layers,  the  outer  one  acting  as  a  periosteum 
to  the  bones.  The  two  layers  are  in  most  places  closely  united,  but  at  others  they 
separate  and  form  sinuses  or  canals,  connected  with  the  veins  and  carrying  \-enous 
blood.  The  falx  cerebri  {Y\<g.  27)  which  is  the  fibrous  partition  separating  the  hemi- 
spheres of  the  brain  from  one  another,  as  well  as  the  tentorium,  which  separates  the 
cerebrum  from  the  cerebellum,  is  formed  by  the  inner  layer  of  the  dura  mater  project- 
ing inward  and  forming  a  partition.  On  the  floor  of  the  skull,  the  dura  mater  accom- 
panies the  nerves  and  gives  them  a  sheath.  The  Gasserian  ganglion  of  the  fifth 
nerve  is  held  in  a  pocket  formed  bv  the  separation  of  the  two  layers  of  the  dura  mater. 

The  cerebral  blood  sinuses  have  already  been  considered.  The  dura  is  nour- 
ished bv  the  meningeal  arteries:  bleeding  from  these  has  already  been  alluded  to 
Cpage  17).  Thin  fibres  of  the  dura  pass  to  the  bone,  also  branches  of  the  meningeal 
arteries  and  veins  pass  to  the  inner  table  and  diploe:  these  all  serve  to  fasten  the 


THE    MENINGES.  21 

dura  to  the  skull.  This  attachment  is  firmest  on  the  base  of  the  skull.  On  the  vault, 
after  an  opening  has  been  made  through  the  skull  by  a  trephine,  the  dura  can  be 
readily  separated  from  the  bone  by  means  of  a  thin,  flat,  steel  spatula.  On  account  of 
the  small  size  of  the  vessels  passing  from  the  dura  to  the  bone,  this  procedure  is  not 
usually  accompanied  by  much  hemorrhage.  In  separating  the  dura  from  the  base  of 
the  skull,  as  is  done  in  operations  on  the  Gasserian  ganglion,  the  bleeding  from  this 
source  is  often  quite  free.  The  dura  is  liable  to  be  torn  in  lifting  it  from  the  bone 
if  the  greatest  care  is  not  exercised. 

The  middle  meningeal  artery,  at  a  distance  of  4  cm.  (ij4  in.)  posterior  to  the 
angular  process  of  the  frontal  bone  and  about  the  same  above  the  zygoma,  usually 
passes  within  the  bone  for  a  distance  of  i  or  2  cm.  Therefore,  in  operating  in  the 
temporal  region,  if  the  dura  is  detached  the  vessel  will  be  torn  and  free  bleeding  vyill 


Fig.  27. — Vault  of  the  skull  opened  and  h 


d,  showing  the  lalx 


follow.  The  vessel  is  liable  to  be  torn  in  endeavoring  to  remove  bony  fragments  in 
fractures  of  this  region.  The  dura  is  also  more  firmly  attached  in  the  median  line; 
and  on  each  side  of  the  median  line  are  the  depressions  in  the  parietal  bone  which 
lodge  the  Pacchionian  bodies.  The  largest  are  usually  located  at  a  distance  of  from 
2  to  5  cm.  posterior  to  a  line  drawn  across  the  skull  from  one  external  auditory 
meatus  to  the  other.  They  are  prolongations  from  the  arachnoid  and  are  surrounded 
by  blood  from  the  longitudinal  sinus. 

The  Arachnoid — also  called  Arachnopia  or  Parietal  Layer  of  the  Pia. 
— The  arachnoid  is  a  thin  fibrous  membrane,  which  passes  over  the  convolutions  of 
the  brain  and  does  not  dip  into  the  sulci  between.  It  is  more  marked  on  the  base 
than  on  the  convexity  of  the  brain.  It  is  not  attached  to  the  dura  above,  and  this 
subdural  space,  while  moist,  contains  little  or  no  free  fluid.  Hemorrhages  do  not 
occur  into  this  space  unless  the  membranes  are  torn,  because  the  bleeding  from  the 
vessels  of  the  dura  is  always  epidural  and  the  arachnoid  derives  its  nourishment  from 
the  pia  mater  below,  so  that  hemorrhages  start  beneath  the  arachnoid,  but  may  rupture 
through  the  arachnoid  into  the  subdural  space.     From  its  under  surface,  fibrils  of  loose 


22  APPLIED    ANATOMY. 

tissue  pass  to  the  pia  mater;  the  space  between  the  fibrous  layer  of  the  arachnoid  above 
and  the  pia  mater  and  convolutions  of  the  brain  below  is  called  the  stibaradmoid 
space.  This  is  a  lymph  space  and  contains  the  cerebrospinal  fluid.  This  fluid  is 
normally  about  60  c. c.  (2  ounces)  in  quantity,  but  in  injuries  to  the  brain  in  which 
the  subarachnoid  space  is  opened,  the  fluid  is  secreted  and  discharged  ver)-  rapidly. 

As  has  already  been  mentioned,  the  arachnoid  sends  a  prolongation  into  the 
internal  auditory  meatus,  hence  a  fracture  through  it  would  open  the  subarachnoid 
space.  This  space  communicates  with  the  ventricles  of  the  brain  through  three 
openings  in  the  pia  mater  at  the  lower  back  portion  of  the  roof  of  the  fourth  ventricle; 
these  are  called  the  foramina  of  Magendie,  Key,  and  Retsms.  The  cerebrospinal 
fluid  extends  down  the  spinal  canal  and  can  be  removed  by  tapping  with  a  trochar,  as 
is  practised  in  the  lumbar  region. 

The  Pia  Mater. —  The  net-work  of  \essels,  with  their  supporting  membrane, 
which  covers  the  convolutions  of  the  brain,  forms  the  pia  mater.  The  fibrils  of  con- 
nective tissue  supporting  the  vessels  are  attached  to  the  fibrous  layer  of  the  arachnoid 
above,  so  that  the  pia  and  arachnoid  are  in  reality  continuous  structures.  The  spaces 
between  these  fibrils  are  often  quite  large  and  communicate  with  each  other,  forming 
the  subarachnoid  space.  The  lower  portions  of  these  fibrils  are  united  and  form  a 
basement  membrane  which  lies  directly  on  the  convolutions  of  the  brain  and  dips  into 
the  sulci.  The  blood-vessels  are  intimately  connected  with  this  lower  pial  membrane 
and  not  with  the  arachnoid  above.  These  vessels  penetrate  into  the  substance  of  the 
brain,  carrying  with  them  a  covering  or  sheath  of  pia  mater.  This  is  called  xh^  peri- 
vascular lymph  sheath  and,  of  course,  communicates  with  the  subarachnoid  space 
above.  These  vessels  nourish  the  brain.  The  perivascular  Ijmiph  sheaths  are  also 
said  to  form  capsules  around  the  great  pyramidal  and  large  glial  cells  of  the  cortex. 

AFFECTIONS  OF  THE  MEMBRANES  OF  THE  RRAIN. 

Both  the  dura  mater  and  the  pia  mater  are  subject  to  inflammation  and  hemor- 
rhages. The  arachnoid  being  practically  a  part  of  the  pia  mater  is  invoh'ed  in  its 
diseases,  so  that  no  mention  is  made  of  it  as  being  separately  affected. 

Inflammation  of  the  Dura  Mater;  Pachymeningitis. — The  outer  surface 
or  inner  surface  of  the  dura  may  be  in\-oh'ed,  constituting  pachymeningitis  externa 
or  interna. 

PachYmeningiiis  Externa.  —  The  external  surface  is  most  often  affected  by 
injuries  from  without,  or  by  extension  of  diseases  from  the  adjoining  bone.  In  cases 
of  fracture  the  inflammation  which  accompanies  healing  frequently  causes  the  dura 
to  become  densely  adherent  to  the  overlying  skull.  This  is  noticed  particularly  when 
trephining  operations  are  performed  for  the  relief  of  focal  or  Jacksoniari  epilepsy. 
Should  the  fracture  be  compound  or  open,  the  occurrence  of  sepsis'  will  tend  to 
involve  the  adjacent  dura  mater.  The  same  occurs  in  cases  of  necrosis.  Syphihtic 
disease  of  the  bones  is  most  apt  to  affect  the  vault  of  the  skull,  while  the  dura 
towards  the  sides  and  base  is  most  often  involved  by  suppurati\'e  ear  disease.  The 
dura  also  becomes  involved  in  tumors  and  gummata. 

Inflammation  of  the  dura  is  not  apt  to  be  a  marked  disease.  It  is  a  very  dense 
membrane  with  few  blood-vessels,  therefore  it  is  quite  resistant  to  inflammatory  proc- 
esses. It  acts  as  a  barrier  to  the  farther  extension  of  an  inflammation  rather  than 
as  a  carrier.  Therefore  we  see  epidural  collections  of  pus  existing  for  a  considerable 
time  without  brain  symptoms  supervening. 

The  dura  mater  contains  the  large  cerebral  venous  sinuses,  and  when  the  inflam- 
matory process  occurs  in  those  regions,  the  sinuses  become  inflamed  and  thrombosis  or 
clotting  occurs.  The  clot  becoming  infected  breaks  down,  the  pus  and  debris  pour  into 
the  general  circulation,  and  general  septicjemia,  and  even  death,  is  caused.  This  is  most 
liable  to  occur  in  the  region  of  the  ear,  where  the  infection  is  apt  to  reach  and  involve 
the  lateral  (transverse)  sinus.     Infection  of  the  longitudinal  sinus  is  much  more  rare. 

PachymeJiingitis  interna  is  an  inflammation  of  the  inner  surface  of  the  dura.  It 
occurs,  to  a  certain  extent,  in  cases  of  gumma  or  other  new  growths  involving  the  inner 
surface  of  the  dura  or  extending  from  the  pia  mater  below.  The  name  pachymeningitis 
interna,  also  called  hEeniorrhagica,  is  usually  restricted  to  a  chronic  inflammation  of 


THE   MENINGES.  23 

the  inner  surface  of  the  dura,  with  the  formation  of  one  or  more  hemorrhagic  mem- 
branous layers.  Adhesions  to  the  pia  do  not  occur.  The  disease  has  been  seen  in 
purpuric  and  infectious  diseases,  as  well  as  in  alcoholic  and  demented  individuals. 

Dural  Hemorrhage. — Hemorrhage  arising  from  injury  to  the  dura  through 
fracture  of  the  skull  has  already  been  discussed  (see  page  18).  Epidural  hemorrhage 
may,  however,  occur  from  an  injury  to  the  skull  and  detach  the  membrane  from 
the  bone  without  a  fracture  being  present.  The  possibility  of  this  occurring  is  proved 
by  the  remarkable  case  reported  by  Dr.  J.  S.  Horsley  (New  York  Med.  Jour.,  Feb. 
9,  1901).  A  man  was  struck  on  the  head  with  a  wooden  club.  He  was  momen- 
tarily stunned,  but  soon  recovered  and  felt  perfectly  well.  An  hour  and  a  half  later  he 
became  drowsy,  and  in  a  few  hours  was  in  a  state  of  stupor.  The  right  side  of  the 
body  and  face  was  paralyzed,  and  the  left  arm  and  leg  were  in  constant  jerking  con- 
vulsions. He  was  trephined  o\'er  the  left  parietal  eminence  and  four  to  six  ounces 
of  blood  clot  removed.  There  was  no  evidence  of  fracture  or  wound  of  the  dura. 
Recovery  was  prompt.      There  have  also  been  other  recorded  cases. 

In  operations  involving  the  separation  of  the  dura  from  the  bone,  bleeding  may 
be  quite  free.  This  comes  from  rupture  of  the  veins  passing  from  the  bone  to  the 
dura,  and  sometimes  from  the  rupture  of  a  vein  passing  over  or  in  the  dura  itself. 

Subdural  hemorrhages  always  originate  from  the  pia  mater. 

Inflammation  of  the  Pia  Mater;  Meningitis. —  This,  when  not  of  a  tuber- 
culous character  is  called  leptomeningitis.  It  is  commonly  known  as  inflammation  of 
the  brain,  or  meningitis.  The  pia  mater  of  the  brain  being  directly  continuous  with 
that  of  the  spinal  cord,  inflammations  of  the  former  extend  to  and  involve  the  latter  in 
about  one-third  of  the  cases.      The  disease  is  then  called  cerebrospinal  meningitis. 

Infection  is  the  usual  cause  of  leptomeningitis.  Direct  injury  to  the  membranes 
and  their  bony  envelopes  may  cause  it,  but  it  occurs  usually  through  some  secondary 
avenue  of  infection.  Thus,  it  may  follow  fractures  opening  into  the  mouth,  nose, 
the  various  accessory  bony  sinuses,  ear,  etc.  The  infection  may,  however,  not  be 
traumatic,  but  occur  through  the  blood,  following  or  accompanying  the  various 
infectious  diseases.  Owing  to  the  fact  of  the  pia  lying  on  the  brain  substance,  and 
its  vessels  with  their  perivascular  sheaths  penetrating  it,  the  disease  naturally  tends 
to  involve  the  brain,  if  it  is  very  severe  or  long  standing.  If  such  is  the  case,  the 
affection  is  called  eercbritis  or  encephalitis. 

The  inflammation  may  be  serous,  plastic,  or  even  purulent.  The  pia  mater  being 
continuous  with  the  choroid  plexuses,  the  ventricles  may  be  dilated  by  the  increased 
fluid.  The  infection  may  follow  the  vessels  into  the  brain  and  produce  brain  abscess. 
The  eflusion  being  often  localized  at  the  base  of  the  brain  interferes  with  the  functions 
of  the  cerebral  nerves.  The  first,  or  olfactory,  is  comparatively  rarely  affected.  The 
optic,  or  second,  is  more  often  so,  producing  intolerance  of  light.  There  may  be 
choked  disk,  and  I  have  even  seen  a  case  in  which  there  was  total  blindness  without 
any  change  being  visible  in  the  nerve  by  means  of  ophthalmoscopy.  In  this  case 
atrophy  of  the  disk  soon  followed.  The  third,  or  motor  oculi,  according  to  Church 
and  Peterson,  is  almost  always  affected.  This  would  be  shown  by  strabismus,  diplopia, 
and  changes  in  the  pupil.  Facial  paralysis,  from  implication  of  the  seventh  nerve,  is 
sometimes  seen,  and  the  auditory,  or  eighth,  may  also  be  affected.  Involvement  of 
the  hypoglossal  or  twelfth  nerve,  will  be  shown  by  deviation  of  the  tongue.  The 
origin  of  the  cranial  nerves  from  the  base  of  the  brain  is  shown  in  Fig.  28. 

Tuberculous  Meningitis.  —  In  this  form  of  meningitis  the  infection  comes  through 
the  blood,  and  the  tuberculous  lesions  follow  the  vessels.  They  are  most  marked  on 
the  base  of  the  brain,  involving  the  circle  of  Willis  and  the  Sylvian  fissure.  The 
infection  follows  the  vessels  of  the  pia  mater  through  the  transverse  fissure  into  the 
ventricles.  The  effusion  accumulating  in  the  ventricles  has  given  rise  to  the  name 
acute  hydrocephalus.  It  also  follows  the  perivascular  sheaths  of  the  smaller  vessels 
into  the  brain  substance,  producing  a  cerebritis;  thus  it  is  seen  how  a  knowledge  of 
the  circulation  of  the  brain  explains  the  location  of  the  lesions. 

The  exudate  involving  the  nerves  of  the  base  of  the  brain  produces  correspond- 
ing symptoms  by  interfering  with  their  function. 

Pial  Hemorrhage. —  Meningeal  hemorrhage  may  be  either  subarachnoid  or 
subdural.      If  the  hemorrhage  has  not  been  violent,  it  spreads  out  under  the  arach- 


APPLIED    ANATOMY. 


noid  in  the  subarachnoid  space.  If,  however,  the  blood  has  escaped  with  consider- 
able force,  it  tears  its  way  through  the  arachnoid  and  spreads  in  the  subdural,  as  well 
as  through  the  subarachnoid  space.  The  origin  of  this  form  of  hemorrhage  is  the 
vessels  o1  the  pia  mater.  The  arachnoid  does  not  give  rise  to  hemorrhages,  neither 
does  the  inner  surface  of  the  dura,  unless  it  has  previously  been  the  seat  of  pachy- 
meningitis interna. 

The  hemorrhage  is  the  result  either  of  injury  or  disease.  In  children  it  is 
usually  due  to  injury;  in  adults  to  either  injury  or  disease.  These  hemorrhages  are 
most  common  in  infancy  and  occur  in  childbirth.  They  are  due  apparently  to 
hard,  protracted  labor  or  injury  done  to  the  child  in  effecting  delivery  by  forceps, 
etc. ,  especially  in  infants  born  before  full  term.  They  are  a  cause  of  idiocy  and  the 
cerebral    palsies    of   childhood.       These    hemorrhages  in    the  new-born    have  been 


phar.M! 
lolh — vagus 
(pneumogas- 
tric) 

nth — spinal 
accessory 


I2th — hypoglossal 


5. — Base  of  brain,  showing  exit  of  cranial 


recognized  by  the  convulsions  they  produce,  and  successful  operations  have  been 
performed  for  their  relief  (see  Harvey  Gushing — "Surgical  Intervention  for  the 
Intracranial  Hemorrhages  of  the  New-born  " — Am.  Jour.  Med.  Sci.,  October,  1905). 
Injuries  received  later  in  life  from  blows  on  the  head  often  produce  subdural  or  pial 
hemorrhages,  without  breaking  the  overlying  bone.  They  are  found  either  at  the  site 
of  impact  or  on  the  side  opposite  that  on  which  the  blow  was  received,  the  latter  being 
produced  by  contre-coup.  When  pial  hemorrhage  occurs  from  disease,  it  is  usually 
from  rupture  of  an  aneurism  of  one  of  the  vessels  of  the  pia  mater.  If  it  does  not  break 
through  the  arachnoid  into  the  subdural  space,  it  may  spread  over  a  considerable 
portion  of  the  cerebral  cortex,  especially  filling  the  sulci.  Unless  the  quantity  is  quite 
large,  so  that  it  interferes  with  the  motor  area,  hemiplegia  will  not  occur.  Convulsions 
may  occasionally  occur  from  irritation  of  the  cortex.  Blood  in  the  subdural  space 
may  travel  along  the  base  of  the  brain  and  into  the  sheath  of  the  optic  nerve. 


THE    BRAIN. 


25 


THE  BRAIN. 

The  affections  of  the  brain  of  most  anatomical  interest  are  those  mvolving  its 
circulation,  the  motor  areas,  and  the  motor  paths.  Paralyses  may  arise  from  (a) 
interference  with  the  motor  areas  in  the  cortex  by  hemorrhages,  injuries,  or  tumors; 
(i)  destruction  of  the  motor  paths  from  the  cortex  to  their  point  of  exit  from  the 
brain;  (c)  injury  of  the  nerves  at  their  exit  from  the  brain. 

Disturbances  of  the  circulation  may  be  either  of  the  nature  of  ansemia  or  ischae- 
mia,  causing  softening,  or  of  congestion,  causing  apoplexy. 

Tumors  of  the  brain  interfere  with  the  functions  of  the  part  in  which  they  are 
located,  as  do  also  wounds.  In  all  of  these  a  knowledge  of  brain  localization  is 
essential. 

THE  CIRCULATION  OF  THE  BRAIN. 

The  blood  reaches  the  brain  by  means  of  the  two  internal  carotid  and  the  two 
vertebral  arteries.      The  vertebrals  enter  through  the  foramen  magnum  and  unite  to 


A.  communicans  poste 
A.  anterolateral 
A.  choroidea 

A.  cerebri  posterior 


Fig.  29. — C 


form  the  basilar,  which  at  the  upper  border  of  the  pons  divides  into  the  two  pos- 
terior cerebrals.  These  give  off  two  small  branches  which  go  to  the  internal  carotids ; 
they  are  the  posterior  communicating  arteries.  The  carotids  divide  into  the  anterior 
and  middle  cerebral  arteries,  the  anterior  communicating  with  one  another  by  means 
of  the  anterior  communicating  artery.  Thus  we  have  the  circ/e  of  Willis  {circitlus 
arteriosus),  formed  hy  \\\e.  posterior  cerebral,  posterior  communicating,  internal  car- 
otid, anterior  cei'ebral,  and  anterior  communicating  arteries  on  each  side. 

The  blood  supply  of  the  brain  is  divided  into  an  anterior  division,  furnished  by 
the  carotids,  and  a  posterior  division,  supplied  through  the  basilar  and  posterior 
cerebrals.  The  communication  branch  running  between  these  two  sets  of  vessels  is 
so  small  that  if  either  is  occluded  the  supply  of  blood  is  practically  cut  of?  from  that 
point  and  ischaemia  results,  at  least  in  most  cases. 

The  anterior  division  is  subdivided  into  a  right  and  a  left  half  by  the  two  carotid 


26 


APPLIED    ANATOiMY. 


arteries.  These  communicate  across  the  median  hne  through  the  anterior  cerebral 
and  anterior  communicating.  Here  again  the  anterior  communicating  branch  is  so 
small  that  it  is  sometimes  unable  to  furnish  blood  to  the  opposite  side  of  the  brain 


Ma\illai>  branch — 5th  1 


when  the  carotid  supply  of  one  side  is  shut  off.      This  may  cause  syncope,  stupor 
or   delirium,   hemiplegia,   and   often  softening   and  death.      These  results  have  not 


A.  cerebri  posterior 
Fig.  31. — Distribution  of  the  A.  cerebri  anterior  and  A. 


rface  of  tbe  brain. 


infrequently  followed  ligation  of  the  carotid  artery  in  cases  of  aneurism.  Obstruc- 
tion of  one  vertebral  artery  would  produce  no  effect  because  circulation  would 
be  restored  by  the  other  vertebral  through  the  basilar. 


THE    BRAIN. 


27 


Internal  Carotid  Artery.— The  internal  carotid  artery  (Fig.  30)  enters  the 
petrous  portion  of  the  temporal  bone,  then  turns  inward  and  upward  through  the  for- 
amen lacerum  medium  then  forward  through  the  ca\einoub  sinus  and  finally  turning 

A.  ceiebri  anterior 


Fig.  32.— Distribut 


surface  of  thi 


d  A.  cerebri  media  on  the  lateral 


Upward  g'i\-es  off  the  ophthalmic  artery;  it  then  pierces  the  dura  mater  just  behind 
the  anterior  clinoid  process,  where,  after  giving  off  the  posterior  communicating 
and  anterior  choroid,  it  divides  into  the  anterior  and  middle  cerebral  arteries. 


Anterior  commiiTiicating 
artery 

Anterior  cerebral  artery- 
Internal  carotid  artery 
Middle  cerel^ral  artery. 

Anterior  choroid  artery 

Posterior  communicat- 
ing artery 


Posterior  cerebral 
artery 


Fig.  33. — Arteries  of  the  base  of  i 


a..  b,.....L.s^f 


Anterior  Cerebral  Artery. — The  anterior  cerebral C  Fig.  31)  passes  forward  and 
inward  over  the  anterior  perforated  space,  between  the  olfactory  and  optic  nerves,  to 
the  median  fissure.  It  gives  of!  the  anterior  communicating  artery  at  this  point,  which 
joins  the  anterior  cerebral  of  the  opposite  side.      The  main  trunk  then  runs  upward 


28  APPLIED    ANATOMY. 

in  the  longitudinal  fissure  on  the  corpus  callosum,  giving  branches  to  the  frontal  and 
parietal  lobes,  and  finally  anastomoses  at  the  posterior  end  of  the  corpus  callosum 
with  the  posterior  cerebral.  This  shows  the  wide  extent  of  brain  tissue  on  the  medi.-?! 
surface  of  the  brain  which  would  be  affected  by  the  blocking  of  this  vessel  by  an 
embolus. 

The  terminal  branches  of  the  anterior  cerebral  spread  laterally  over  the  surface 
of  the  brain  (Fig.  32 j  outward  from  the  longitudinal  fissure  for  a  short  distance, 
about  2  cm.  As  it  crosses  the  anterior  perforated  space,  it  gives  off  the  antero- 
median perforating  rganglionic)  arteries  which  pierce  the  lamina  cinerea  to  supply 
the  anterior  portion  of  the  caudate  nucleus  above. 

Middle  Cerebral  Artery, —  The  middle  cerebral  artery  passes  upward  and 
outward  in  the  fissure  of  Sylvius,  di\dding,  when  opposite  the  island  of  Reil,  into  the 
branches  which  supply  the  cortex  of  the  brain  (see  Fig.    32).      On  its  way  toward 


. Medulla  oblongata 

,'^ Decussation 

Fig.  34. — Showing  the  degenerative  and  apoplectic  areas  of  the  brain  and  the  course  pursued  by  the  motor 
fibres  from  the  corte-x,  through  the  internal  capsule,  crura,  pons,  and  medulla  to  the  decussation,  where  they 
cross  the  median  line  to  supply  the  opposite  side  of  the  body. 

the  island  of  Reil,  at  the  commencement  of  the  fissure  of  Sylvius,  many  small  straight 
branches  enter  the  brain  substance  to  supply  the  basal  ganglia.  Two  or  three  supply 
the  caudate  nucleus,  others,  called  the  anterolateral  perforating  (ganglionic),  enter 
the  anterior  perforated  space  to  supply  the  lenticulostriate  ganglion  and  the  anterior 
portion  of  the  thalamus.  One  of  the  largest  of  these  arteries,  the  lenticulostriate,  has 
been  called  the  artery  of  cerebral  hemorrhage ,  by  Charcot,  on  account  of  the  frequency 
with  which  it  is  found  ruptured  in  cases  of  apoplexy  (Fig.  33). 

Anterior  Choroid. — The  anterior  choroid  artery  comes  sometimes  from  the 
internal  carotid  and  sometimes  from  the  middle  cerebral.  It  passes  backward  and 
outward  on  the  optic  tract  and  crus  cerebri  and  enters  the  transverse  fissure  at  the 
descending  horn  of  the  lateral  ^'entricle.    It  ends  in  the  choroid  plexus  (see  F"ig.  33). 

Posterior  Cerebral  Artery. — The  posterior  cerebral  artery  passes  outward  over 
the  crus  cerebri,  just  above  the  pons,  to  the  under  surface  of  the  posterior  portion  of 
the  cerebral  hemisphere.  Before  it  receives  the  posterior  communicating  artery  it  gives 
off  the  posteromedian  perforating  (ganglionic)  arteries,  which  enter  the  posterior 
perforated  space  to  supply  the  thalamus  and  third  ventricle.     Just  beyond  the  poste- 


THE    BRAIN. 


29 


rior  communicating  artery  it  gives  off  the  posterolateral  perforating  (ganglionic) 
arteries,  which  supply  the  posterior  portion  of  the  optic  thalamus,  crus  cerebri,  and 


Uptl 
Ootic  ch 


Middle 
Choroid  pie 
Foramen  of  Mo 
Septum  lucidum        / 


Velum  interpositum 


Pituitary  body 

Mammillary  body 

Aqueduct  of  Sylvius 


4th  ventricle 
Fig.  35.  -Medial  section  of  the  br; 


corpora  quadrigemina.  The  branches  to  the  cortex  supply  a  small  portion  of  the 
inferior  surface  of  the  temporosphenoidal  lobe  and  the  occipital  lobe  as  seen  in 
Figs.  31  and  32. 


"^, 


Fig.  36.— Horizontal  section  of  brain ;  the  corpus  callosum  and  forni.x  have  been  removed,  exposing  the  lateral 
ventricles,  with  the  caudate  nuclei  projecting  into  them  anteriorly  and  the  velum  interpositum  farther  back,  with 
the  choroid  plexus  at  the  sides  and  the  veins  of  Galen  nearer  the  middle  line.  The  lateral  ventricles  in  this  brain 
are  somewhat  larger  than  usual. 


30 


APPLIED    AXATU-MY. 


Cerebral  Softening. — This  occurs  in  the  young  from  emboHsm;  it  then  affects 
the  cortex,  but  the  more  common  variety  is  caused  by  thrombosis  in  arteries  which 
are  diseased,  usually  in  the  aged.  The  part  farthest  from  the  source  "of  blood 
supply  is  the  most  apt  to  suft'er,  therefore  we  find  it  occurring  most  frequently  in 
the  anterior  capsuloganglionic  region,  just  above  the  usual  site  of  apoplexy  (Fig.  34). 
The  affected  area  will  be  seen  to  be  most  remote  from  both  the  cortical  and  basal  blood 
supply.  The  perforating  arteries  supplying  this  region  are  in  the  nature  of  terminal 
branches  and  do  not  anastomose  to  any  extent  either  with  each  other  or  with  the 
branches  coming  from  the  cortex,  hence  their  occlusion  inflicts  irreparable  damage. 

Apoplexy. — By  apoplexy  is  meant  the  rupture  of  a  blood-vessel  with  conse- 
quent extravasation  of  blood,  either  in  or  on  the  brain.  It  mav  occur  in  anv  portion 
of  the  brain,  and  either  from  the  arteries  of  the  Sase,  or  from  the  smaller  arteries  of 


Lateral  ventricle 


Caudate  nucleus 


Lenticular  nucl 

Claustrum 


Interna!  capsul    _ 
posterior  limb  ; 


Corpora  quadrig 


Septum  luciriuin 
Fonii.x — anterior  pilla 


Fig. 37. — Horizontal  section  of  the  brain,  showing  the  internal  capsule  and  its  relation  to  the  lateral  ventricles. 


the  co)-te.x.  The  former  is  the  more  frequent.  The  arteries  that  most  often  rupture 
are  the  branches  of  the  middle  cerebral  which  enter  the  anterior  perforated  space, 
especially  its  outer  portion.  One  of  the  largest  of  these  anterolateral  arteries,  as  has 
already  been  mentioned,  known  as  the  lenticulostriate,  has  been  called  bv  Charcot 
the  artery  of  cerebral  hemorrhage. 

The  portions  of  the  brain  usually  affected  are  the  posterior  portion  of  the  len- 
ticular nucleus,  internal  capsule,  and  surrounding  parts. 

Figure  35  is  a  medial  section  of  the  brain,  giving  a  lateral  view  of  the  ventricles. 

Figure  36  is  a  horizontal  transverse  section  of  the  brain,  opening  up  the  ventri- 
cles. In  front  are  seen  the  two  lateral  ventricles,  separated  bv  the  septum  lucidum. 
The  cavitv  shown  in  the  septum  lucidum  is  the  so-called^/?//  ventricle.  The  round 
body  bulging  into  the  lateral  ^•entricle  and  forming  its  floor  is  the  caudate  niiclciis 
portion  of  the  corpus  striatum.  The  third  ventricle  is  posterior  and  below  the  lateral 
ventricles,  and  extends  from  the  septum  lucidum  in  front  to  the  posterior  pillars  of 
the  forni.x  behind.  It  extends  from  side  to  side  as  one  large  cavity  with  no  median 
partition.  Bulging  into  the  third  ventricle  on  each  side  are  the  (optic^  tlialami. 
They  are  separated  from  the  corpora  striata  by  some  white  fibres,  the  tcsnia  semicircu- 
laris.     To  the  inner  side  of  the  taenia  semicircularis  is  seen  the  choroid  plexus,  whicli 


THE    BRAIN. 


31 


runs  down  anteriorly  over  the  thalamus  to  the  foramen  of  Monro,  through  which 
it  enters  the  lateral  ventricle.  Two  large  veins,  the  vems  of  Galen,  pass  down 
near  the  middle  line  of  the  third  \entricle  to  empty  into  the  straight  simcs.  Pos- 
teriorly, the  choroid  plexus  follows  the  descending-  horn  of  the  lateral  ventricles. 
The  choroid  ple.xus  hangs  from  the  under  surface  of  the  velum  interpositum,  which 
is  a  fold  of  the  pia  mater  entering  through  the  transverse  fissure.  The  veins  of  Galen 
run  between  the  two  layers  of  the  velum  interpositum. 

Turning  now  to  Fig.  37,  showing  a  somewhat  deeper  transverse  horizontal 
section,  running  through  the  corpus  striatum  and  thalamus,  it  will  be  seen  that  to 
the  outer  side  of  the  corpus  striatum  and  thalamus  is  a  white  layer  constitut- 
ing the  internal  capsule.  It  divides  the  corpus  striatum  into  two  parts,  one  to  its 
inner  side,  which  projects  into  the  lateral  ventricle,  called  the  caudate  nucleus,  and 


Fig.  38.—! 
fibres  from  the 
cross  the  mediai 


howing  the  degenerative  and  apoplectii 
corte.^,  throu,o;h  the  internal  capsule,  c 
line  to  supply  the  opposite  side  of  the  body. 


the  other  to  its  outer  side,  called  the  lenticular  nucleus.  To  the  inner  side  of  the 
posterior  portion  of  the  lenticular  nucleus  and  internal  capsule  is  seen  the  thal- 
amus. To  the  outer  side  of  the  lenticular  nucleus  one  sees  other  white  fibres  called 
the  external  capsule.  An  apoplectic  hemorrhage  occurring  in  the  lenticular  nucleus 
or  internal  capsule  may  push  forward  and  rupture  into  the  lateral  ventricle.  It  may 
go  backward  and  involve  the  anterior  portion  of  the  thalamus  and  burst  into 
the  third  ventricle,  and  if  it  extends  outward  it  involves  the  external  capsule.  Some- 
times, if  the  hemorrhage  is  low  down,  it  ruptures  downward  through  the  base  of  the 
brain,  showing  itself,  of  course,  at  the  anterior  perforated  space.  Fig.  38  shows  these 
structures  as  seen  in  a  medial  section  of  the  brain. 

In  Fig.  38  there  is  a  coronal  transverse  section  of  the  brain,  showing  the  course 
of  fibres  of  the  internal  capsule  from  the  cortex  of  the  brain  through  the  corpus 
striatum,  between  the  lenticular  and  caudate  nuclei  :  then,  forming  the  cms  cerebri, 
the  fibres  pass  through  the  pons  and  medulla  to  enter  the  spine,  decussate,  and 
pass  to  the  extremities.  This  constitutes  the  motor  pathway  from  the  cortex  to  the 
extremities,  and  when  it  is  injured  in  apoplexy,  the  e.xtremities  of  the  opposite  side 
are  paralyzed. 


32 


in  other  portions  of  the  brain. 


APPLIED    ANATOMY. 

Hemorrhage  into  the  Pons— Crossed  Paralysis.— Apoplexy  may  also  occur 
It  may  occur  in  the  pons  (^see  Fig.  39  ).  This  produces 
two  different  sets  of  symptoms,  accord- 
ing to  its  location,  which  is  due  to 
the  fact  that  the  fibres  of  the  seventh 
or  facial  ner\-e,  in  their  passage  from 
the  cortex  to  the  face,  decussate  in  the 
pons.  If  a  small  hemorrhage  occurs 
into  the  upper  portion  of  the  pons,  it 
■will  destroy  the  motor  fibres  to  the 
face  and  the  extremities  of  the  oppo- 
site side.  If,  however,  the  hemor- 
rhage is  below  the  point  of  decussa- 
tion, the  side  of  the  face  on  the  side  of 
the  lesion  will  be  paralyzed  and  the 
extremities  of  the  opposite  side,  thus 
producing  what  is  known  as  crossed 
paralysis,  that  is,  a  paralysis  of  the  face 
on  one  side  and  of  the  extremities  on 
the  other. 

Cortical   Apoplexy. —  Hemor- 

Fic.  39— Diagram   illustrative  of  crossed  paralysis.    A  ^l-acTPs  of    thf  rr.rtpv  arp  ant  to  he  IPS'; 

clot  in  the  upper  portion  of  the  pons  causes  paralysis  of  the  rnages  OX    tne  COrteX  are  apt  tO  DC  iCbb 

muscles  of  the  face  and  extremities  of  the  same  side  of  the  Jj^    extent    and    more    localized    On    ac- 

bodv.   A  clot  in  the  lower  portion  ot  the  pons  causes  paralv-  .                         ,,           .             .     . 

sis  of  one  side  of  the  face  and  the  extremities  of  the  opposite  COUnt    of    the    Smaller  Size    Of    the  VCS- 

sideofthebody.  sels  affected.     They  either  destroy  or 

irritate  the  brain  at  the  site  of  injury,   and   produce,  if  they  in\-olve  certain  areas 
of  the  brain,  definite  peripheral  symptoms  which  ser\  e  to  indicate  the  seat  of  lesion. 


THE  CEREBRAL  LOBES. 

Each  cerebral  hemisphere  is  composed  of  fi\-e  lobes,  called  the  froiital,  parietal, 
occipital,  tcii!po)'osplicnoidaI,  saxA  central,  o\-  island  of  Reil. 

The  frontal  lobe  comprises  the  anterior  portion  of  the  brain,  as  far  back  as  the 
fissure  of  Rolando  or  central  sulcus,  and  as  far  toward  the  base  as  the  fissure  of  Sylvius. 


piial  Icbe 


Temporal  lobe 


Lobes  of  the  brain. 


The  parietal  lobe  extends  from  the  fissure  of  Rolando  (central  sulcus)  in  front 
to  the  parieto-occipital  fissure  behind.  Below,  it  is  limited  anteriorly  by  the  fissure 
of  Sylvius,  while  its  posterior  portion  merges  into  the  temporosphenoidal  lobe. 

The  occipital  lobe  extends  posteriorly  from  a  line  joining  the  occipitoparietal 
fissure  abo\-e  to  the  pre-occipital  notch  below. 

The  temporosphenoidal  lobe  consists  of  that  portion  of  the  brain  below  the 
fissure  of  Svlvius,  as  far  back  as  the  pre-occipital  notch.  It  occupies  the  middle 
fossa  of  the  skull. 


THE    BRAIN. 


33 


The  central  lobe  or  island  of  Reil,  also  called  the  insula,  consists  of  five 
to  seven  convolutions  which  radiate  upward;  it  can  be  seen  by  separating  the  two 
sides  of  the  anterior  portion  of  the  fissure  of  Sylvius. 

THE    FISSURES    AND    CONVOLUTIONS    OF   THE    BRAIN. 

The  surface  of  the  brain  is  wrinkled  or  thrown  into  folds,  producing  elevations 
and  depressions.  The  elevations  are  called  convolutions  or  gyri,  and  the  depres- 
sions, fissures  or  sulci. 

The  fissures  are  called  main  or  subsidiary  fissures,  according  to  their  impor- 
tance. The  five  main  fissures  are  the  longitudinal  fissure,  which  separates  the 
hemispheres;  the  transverse  fissure,  which  separates  the  cerebrum  and  cerebellum 
and  communicates  with  the  third  ventricle;  {\iQ  fissure  of  Sylvius ;  ihz  fissure  of 
Rolando,  or  central  fissure,  and  the  parieto-occipital fissure. 


THE  LATERAL  SURFACE  OF  THE  HEMISPHERES. 

The  frontal  lobe  has  a  superior,  an  inferior,  and  a  precentral  sulcus.     The  first 
two  divide  the  anterior  portion  into  the  superior,  middle,  and  inferior  firontal  co7ivo- 


Sulcus  preccentral: 


centralis  (Rolandi) 
Iralis 
Sulcus  iiilerparietali: 


Sulcus  frontalis 

supei 


Sulcus  frontal 


Sulcus  temporalis  supei 

Sulcus  lemporalis  medius 

Fig.  41. — Fissures,  sulci,  and  gyri  {con\c 


s)  of  the  lateral  surface  of  the  cerebral  hemisphere. 


lutions.  That  portion  of  the  inferior  or  third  left  frontal  convolution  which  surrounds 
the  ascending  limb  of  the  fissure  of  Sylvius  is  called  Brocd s  co7ivohdion,  and  is 
the  ce7itre  for  speech.  Posterior  to  these  and  running  upward  and  backward,  form- 
ing the  anterior  wall  of  the  central  fissure,  is  the  precentral  or  ascending  frontal 
convolutio7i. 

The  convolution  forming  the  anterior  extremity  of  the  parietal  lobe  and  the 
posterior  wall  of  the  central  sulcus  or  fissure  of  Rolando  is  called  the  postcentral  or 
ascending  parietal  co7ivoliition.  Immediately  behind  it  is  the  postcentral  or  inter- 
parietal sulcus.  The  upper  portion  of  this  sulcus  divides,  one  branch  going  up- 
ward and  one  backward.  Immediately  above  the  posterior  branch  is  the  superior 
parietal gy7-us  or  lobule,  and  below  it  and  surrounding  the  posterior  e.xtremity  of  the 
fissure  of  Sylvius  is  the  supramarginal gyrus.  Posterior  to  the  supramarginal  gyrus 
and  surrounding  the  posterior  extremity  of  the  superior  temporal,  or  temporosphe- 
noidal  sulcus  is  the  convolution  known  as  the  angular  gy7'us. 

The  occipital  lobe  on  its  convex  surface  is  di\'ided  into  supei-ior  and  inferior 
occipital  convolutio7is  by  the  lateral  occipital  sulcus. 

The  temporal  or  temporosphenoidal  lobe  is  also  divided  into  superior.  77iiddle, 
and  inferior,  or  first,  second,  and  third  temporal  convolutions  by  the  superior,  or  par- 
allel, and  middle  fissures.  On  the  under  surface  is  a  fourth  tempoi-al  convolution, 
separated  from  the  third  by  the  inferior  temporal  fissure.  These  fissures  may  not  be 
distinct. 


34 


APPLIED    ANATOMY. 


THE  iMEDIAL   SURFACE   OF    THE   HEMISPHERES. 


If  now  the  medial  surface  of  the  hemisphere,  which  forms  one  side  of  the  longi- 
tudinal fissure,  be  examined,  there  is  seen  a  large  convolution  running  just  above  and 
parallel  with  the  corpus  callosum.  It  is  called  the^_77'«.s-  cingidi  {^fornicatus).  Below 
and  separating  it  from  the  corpus  callosum  is  the  callosal  fissure;  above  it  is  the  calloso- 
marginal  fissure.  The  convolution  above  the  latter,  forming  the  margin  of  the  hem- 
isphere, is  the  marginal  convohdion.  The  callosomarginal  fissure  at  its  posterior 
portion  turns  upward  and  ends  on  the  margin  of  the  hemisphere,  just  posterior  to  the 
fissure  of  Rolando,  or  central  fissure,  and  ser\'es  to  identify  it.  This  marks  the  pos- 
terior limit  of  the  frontal  lobe.  The  posterior  end  of  the  frontal  lobe  surrounds  the 
upper  end  of  the  central  fissure  and  on  that  account  is  called  the  pai'acentral  lobule. 
Its  anterior  boundary  is  marked  by  the  paracentral  fissure,  or  sulcus.  Between  the 
callosomarginal  fissure  in  front  and  the  parieto-occipital  fissure  behind  is  the  parietal 
lobe,  called,  from  its  square  shape  on  the  medial  surface,  the  quadrate  lobule,  or  from 
being  anterior  to  the  cuneus  lobule,  the  precuneus.      Running  downward  and  back- 


Sulcus  cinguli  (callosoniarginalis) 


Fissura  collateral 

Sulcus  temporalis  inferior 

Fig.  42.— Gyri,  sulci,  and  fissures  of  the  medial  surface  of  the  cerebral  hemisphere. 

ward  from  the  deeper  portion  of  the  parieto-occipital  fissure  is  a  verv'  distinct  depres- 
sion called  the  calcarine  fissure.  These  Uvo  fissures  include  a  wedge-shaped  piece 
of  the  occipital  lobe  called,  from  its  shape,  the  cuneus  lobule.  It  is  of  interest  in 
reference  to  the  sense  of  sight. 


FUNCTIONS  OF  THE  CORTEX  OF  THE  BRAIN 
LOCALIZATION. 


CEREBRAL 


A  knowledge  of  the  functions  of  the  various  portions  of  the  brain  is  necessary 
in  order  to  localize  a  diseased  area.  The  diseases  and  injuries  to  which  the  brain 
is  exposed  oftentimes  do  not  involve  the  whole  brain,  but  only  certain  distinct  and 
isolated  parts.  The  brain  is  not  a  single,  homogeneous  organ  that  acts  only  as  a 
whole;  it  is  complex.  It  is  composed  of  a  number  of  separate  parts  or  areas,  which 
may  act  either  singly  or  in  conjunction  with  other  areas.  These  separate  areas  have 
different  functions,  so  that  if  the  disease  or  injury  is  limited  to  one  of  them,  we  have 
its  functions  abolished,  and  the  S3anptoms  produced  indicate  the  area  affected. 

These  areas  are  situated  on  the  surface  or  cortex  of  the  brain  in  the  gray  matter. 
They  receive  impressions  from,  and  transmit  impulses  to,  all  parts  of  the  body 
through  the  white  matter  or  fibres  of  the  brain.  An  injury  to  the  cortex  or  gray 
matter  destroys  the  originating  and  receptive  centres.  An  injury-  to  the  white  matter 
destroys  the  paths  to  and  from  these  centres  and  therefore  prevents  them  from 
receiving  impressions  or  sending  out  impulses.  Thus,  we  may  have  a  paralysis  of 
the  leg  and  arm  caused  by  an  injury  to  the  leg  and  arm  centres  in  the  cortex  of 
the  brain,  as  bv  a  hemorrhage  from  a  fracture,  or  we  can  ha\-e  the  same  paralysis 


THE    BRAIN. 


35 


produced  by  an  injury  to  the  path  leading  from  those  centres,  the  motor  tract  as  it 
is  called,  by  a  hemorrhage,  as  from  apoplexy,  involving  the  corresponding  white 
matter  fibres. 

The  e-\act  localization  of  the  functions  of  all  parts  of  the  brain  has  not  been 
accomplished,  but  the  functions  of  many  areas  have  been  definitely  proven.  In 
cases  of  brain  tumor,  abscess,  hemorrhage,  injury,  etc. ,  a  knowledge  of  these  areas 
enables  one  to  localize  the  seat  of  the  lesion. 


FUNCTIONS  OF  THE  CONVOLUTIONS  ON  THE  SURFACE  OF  THE  CEREBRUM. 

The  frontal  lobe  may  be  conveniently  divided  into  three  areas;  prefrontal,  mid- 
frontal,  and  postfrontal.  The  prefrontal  area  embraces  all  the  superior,  middle, 
and  inferior  frontal  convolutions,  with  the  e-\ception  of  their  posterior  ends.  On 
the  medial  side  it  reaches  to  the  callosomarginal  fissure.  The  function  of  the  pre- 
frontal area  is  said  to  be  that  of  higher  cerebration,  as  attention,  judgment,  and  com- 
parison. This  region,  particularly  the  lower  portion,  is  liable  to  injury,  owing  to  its 
anterior  position  and  to  the  fact  that  it  overlies  the  orbit.  The  roof  of  the  orbit  is 
quite  thin  and  liable  to  fracture  by  penetrating  bodies,  as  umbrellas,  canes,  etc. 
Sometimes  a  portion  of  this  part  of  the  brain  may  be  destroyed  without  marked 
interference  with  the  mental  qualities  of  the  patient.      This  occurred  in  the  case  of  a 


face  of  the  brain. 


boy  who  was  struck  in  the  eye  by  a  carriage  pole  (personal  observation).  The  eye 
was  burst,  necessitating  its  removal.  Several  pieces  of  the  fractured  bone  of  the 
roof  of  the  orbit  were  removed  and  brain  tissue  came  away  for  several  days.  The 
boy  recovered  and  for  si.xteen  years  apparently  had  no  resulting  mental  deficiency. 

The  midfrontal  area  embraces  the  posterior  portion  of  the  superior  and 
middle  convolutions,  with  the  upper  posterior  portion  of  the  inferior.  It  is  con- 
cerned in  certain  mo\ements  of  the  eyes  and  lids,  and  also  in  turning  the  head 
toward  the  opposite  side.  This  midfrontal  division  is  the  most  anterior  portion  of 
what  is  called  the  motor  area. 

Speech  Centre,  or  Broca's  Convolution. — The  centre  of  speech  is  located 
in  right-handed  people  in  the  posterior  portion  of  the  third  left  frontal  convolution, 
where  it  arches  around  the  ascending  limb  of  the  fissure  of  Sylvius.  It  is  called 
Broca's  convolution.  The  faculty  of  writing  or  written  speech  is  attributed  to  the 
graphic  centre  in  the  posterior  extremity  of  the  second  frontal  convolution  just  above 
and  behind  Broca's  convolution. 

The  postfrontal  area  embraces  the  ascending  frontal  convolution  in  front  of 
the  fissure  of  Rolando  or  central  fissure.  It  is  concerned  in  the  \-arious  movements 
of  the  trunk  and  extremities,  and  forms  the  anterior  portion  of  the  Rolandic  area; 
it  will  be  considered  under  that  head. 

The  Rolandic  Area. — This  is  the  area  which  gi\'es  rise  to  most  of  the  voluntary 
movements  of  the  body.      When  affected,  it  causes  positive  symptoms  of  paralysis 


36 


APPLIED    ANATOMY. 


or  contraction  of  the  muscles  connected  with  it,  and  is  the  region  most  frequently 
affected  by  injuries.  This  is  partly  due  to  the  fact  of  its  pro.ximity  to  the  middle 
meningeal  artery,  as  a  hemorrhage  from  that  vessel  produces  a  clot  which  covers 
and  involves  this  area. 

The  Rolandic  area  embraces  the  ascending  frontal,  or  precentral,  and  posterior 
portion  of  the  three  frontal  convolutions,  the  former  being  in  front  of  the  fissure 


Fig.  44. — Diagram  illustratin. 


motor  areas  of  the  lateral  surface  of  the  brail 


of  Rolando,  or  central  fissure.  The  fissure  of  Rolando  passes  downward  and  for- 
ward from  the  longitudinal  fissure,  at  an  angle  of  about  70°,  nearly  to  the  fissure  of 
Sylvius,  being  separated  from  it  by  the  joining  of  the  ascending  parietal  and  ascend- 


probable  functions  of  the  gyri  (convolutions)  of  the 


rface  of  the  brail 


ing  frontal  convolutions.      Sherrington  and  Griinbaum  have  shown  that  the  motor 
area  is  almost  exclusively  anterior  to  the  central  fissure. 

The  upper  portion  of  the  motor  area,  near  the  longitudinal  fissure,  is  concerned 
with  the  movements  of  the  toes  and  lower  extremity.  The  leg  centres  are  toward 
the  upper  end  of  the  central  fissure;  next  are  those  of  the  abdomen  and  chest. 
The  arm  centres  are  toward  the  middle,  and  the  face  centres,  including  the  larynx, 


THE    BRAIN. 


37 


tongue,  and  platysma  myoid  muscle,  around  its  lower  extremity.  The  leg,  arm,  and 
face  centres  are,  respectively,  opposite  the  posterior  extremities  of  the  superior, 
middle,  and  inferior  frontal  convolutions. 

The  upper  portion  of  the  motor  area  passes  over  the  upper  margin  of  the  hemi- 
sphere and  down  on  its  medial  side  almost  as  far  as  the  callosomarginal  fissure  and 
paracentral  lobule. 

The  Sensory  Area. — The  portions  of  the  cerebrum  involved  in  cutaneous 
and  muscular  sensibility  embrace  the  posterior  portion  of  the  parietal  convolutions, 
the  precuneus  or  quadrate  lobule,  and  gyrus  fornicatus  as  far  forward  as  the  motor 
area  on  the  medial  aspect. 

The  visual  area  embraces  the  occipital  lobe,  particularly  its  cuneus  lobule, 
and  region  of  the  calcarine  fissure  on  the  medial  surface  of  the  hemisphere.  The 
anterior  portion  of  the  occipital  lobe  and  the  region  of  the  angular  gyrus  are  con- 


Ventriculum  lateralis 

Corpus  striatum 

Commissura  auterior 


Ventriculum  teiliu 
Pjii 
Ventriculum   ^u-^itu 
Medulli 
Fig.  46. — Foreshortened 


Commissura  posterior 
Corpus  pineaie 


Corpora  quadrigeu 


m3^ 


cerned  in  the  more  complex  phenomena  of  sight,  and  their  destruction  produces 
word-blindness.  Destruction  of  the  centres  on  both  sides  produces  what  has  been 
called  mind-blindness,  because  objects  can  no  longer  be  recognized. 

The  Auditory  Area. — The  centre  for  hearing  is  located  in  the  superior  and 
middle  temporosphenoidal  convolutions.  It  requires  destruction  of  these  convo- 
lutions on  both  sides  of  the  brain  to  produce  total  cerebral  deafness.  The  memory 
or  recognition  of  spoken  words  (word  hearing)  is  apparently  performed  by  the  pos- 
terior ends  of  the  superior  and  middle  (ist  and  2d)  temporosphenoidal  convolutions. 

Gustatory  Area. — The  sense  of  taste  is  supposed  to  be  located  on  the  under 
and  inner  surfaces  of  the  temporosphenoidal  lobe  or  fourth  temporal  convolution. 

Olfactory  Area. — The  sense  of  smell  is  supposed  to  involve  the  anterior  portion 
of  the  gyrus  fornicatus  and  the  upper  medial  portion  of  the  temporosphenoidal  lobe. 

The  cerebral  areas  for  both  smell  and  taste  have  not  been  as  yet  accurately 
determined. 

FUNCTIONS  OF  THE  BASAL  GANGLIA. 

Corpus  Striatum  and  Thalamus. — The  exact  functions  of  the  corpus  stria- 
tum, embracing  the  caudate  and  lenticular  nuclei,  and  of  the  thalamus  are  not 
known.  Thev  are  most  often  affected  in  apoplexies ;  lesions  of  the  corpus  striatum  are 
accompanied  by  disturbances  of  motion,  and  those  of  the  thalamus  by  disturbances  of 
sensation. 


APPLIED    ANATOMY. 


Corpora  Quadrigemina. — The  anterior  corpora  quadrigemina  are  associated 
with  sight,  the  posterior  possibly  with  hearing  and  equihbrium.  Note  their  prox- 
imity to  the  cerebellum. 


Spinal  cord 


Cerebral  cortex 


Crura  Cerebri. — The  crura  cerebri  transmit  both  sensor)'  and  motor  impulses. 
Note  their  pro.ximity  to  the  third  nerve,   as  they  are  apt  to  be  involved  by  the 

same  lesions,  thus  accounting  for  paralyses 
or  sensorv  disturbances  of  the  trunk  or  ex- 
tremities accompanied  by  ocular  paralysis. 
Pons  Varolii. — The  ]3ons  transmits 
the  motor  or  p^•ramidal  tract,  and  also  the 
fifth,  sixth,  and  se\enth  ner\'es.  Implication 
of  the  seventh  or  facial  nerve,  together  with 
the  motor  tract,  has  already  been  alluded  to 
(page  32  ).  If  the  sixth  or  abducent  nerve 
is  in\'olved,  the  external  rectus  muscle  on 
that  side  will  be  paralyzed.  If  the  fifth,  or 
trifacial  ner\e  is  affected,  irritation  of  its 
motor  root  may  produce  trismus  or  clench- 
ing of  the  ia^^•s,  and  interference  \\'ith  its 
sensory  root  may  cause  antesthesia  of  one 
side  of  the  face. 

THE   CORONA   RADIATA,   INTERNAL 
CAPSULE,  AND  MOTOR  TRACT. 

The  co7'ona  radiata  is  the  bundle  of  white 
fibres  which  spreads  out  like  a  fan  and  con- 
nects the  cortex  of  the  brain  with  the  basal 
ganglia  and  spinal  cord.  Proceeding  down- 
ward from  the  cortex,  the  corona  radiata  be- 
comes smaller  and  passes,  in  the  form  of  a 
band,  between  the  lenticular  nucleus  on  the 
outside  and  the  caudate  nucleus  and  thal- 
amus on  the  inside.  This  band  is  known 
as  the  internal  capsule.  It  transmits  in  its 
anterior  portion  fibres  from  the  prefrontal  or 
higher  psychical  area;  then  come  the  motor 

paths ;  and  still  farther  back,  in  the  posterior  third  of  the  posterior  portion,  sensory  fibres. 
The  functions  of  the  external  capsule,  which  lies  to  the  outer  side  of  the  lenticular 

nucleus,  are  not  known. 


decussation 
Lateral 

pyramidal  tract 
Direct 

pyramidal  tract 


Fig.  48. — Diagram  showing:  course  an 
tion  of  corticospinal  (pyramidal)  tract  ;  M, 
P.pons;  CP.  cerebral  peduncle;  T,  thalan] 
caudate  and  lenticular  nuclei ;  CC,  corpus 
(Piersol.) 


THE    BRAIN. 


39 


The  motor  fibres  of  the  internal  eapsule  pass  downw^ard  through  the  anterior 
portion  of  the  crus  cerebri  and  pons  into  the  medulla,  at  the  lower  part  of  which 
the  majority  decussate  and  pass  into  the  anterior  columns  of  the  cord  as  the  pyram- 
idal tracts.  Thus,  it  is  seen  that  destruction  of  any  portion  of  the  motor  tract, 
from  the  point  oi pyramidal  decussation  below,  through  the  internal  capsule  to  the 
cortex  above,  will  cause  a  paralysis  on  the  opposite  side  of  the  body. 


CRANIOCEREBRAL  TOPOGRAPHY. 

For  the  purpose  of  operating  on  the  brain  it  is  essential  to  know  the  bony  land- 
marks of  the  skull,  the  lower  level  of  the  brain,  and  the  relation  which  the  various 
fissures  and  convolutions  bear  to  the  surface. 

The  most  important  fissures  are  x\\&  longitudinal,  Sylvian,  Rolandic,  2i\\6i parieto- 
occipital. If  these  can  be  properly  located,  the  convolutions  and  subsidiary  fissures 
can  be  readily  filled  in. 

BONY    LANDMARKS. 

Nasion. —  The  nasofrontal  suture  in  the  median  line. 

Glabella.  — The  smooth  spot  in  the  median  line  on  the  frontal  bone  between 
the  superciliary  ridges.      It  is  about  on  a  le\-el  with  the  upper  edge  of  the  orbit. 


Stepha 


Glabella 

\-  \ternal  angular  process 


Lambda.  J  \,(    (. 


Bregma. —  The  point  in  the  midline  where  the  sagittal  and  coronal  sutures 
cross.      It  corresponds  with  the  anterior  fontanelle  in  the  infant. 

Lambda. —  The  point  of  meeting  of  the  sagittal  and  lambdoid  sutures.  It  is 
about  6  cm.  (2)^  in. )  above  the  occipital  protuberance. 

Inion. — The  external  occipital  protuberance. 

Pterion. —  This  name  was  given  by  P.  Broca  to  the  point  where  the  frontal, 
parietal,  and  sphenoid  bones  meet  in  the  region  of  the  temple.  It  is  about  2.5  cm. 
( I  in. )  behind  the  angular  process  and  should  not  be  confounded  with  the  Sylvian 
point,  which  is  1.5  cm.  {i/^  in.)  farther  posterior,  where  the  temporal,  parietal,  and 
sphenoid  bones  meet.  Horsley  called  this  latter  point  the  pterion.  The  region  of 
the  pterion  is  the  seat  of  the  anterolateral  fontanelle  in  the  fcetus. 

Asterion.—  This  lies  2  cm.  (4  in.)  behind  the  base  of  the  mastoid  process, 
where  the  parietal,  occipital,  and  temporal  bones  meet.  It  is  on  the  superior  curved 
line  and  in  fetal  life  forms  the  posterolateral  fontanelle. 

Temporal  Ridge. —  This  marks  the  upper  attachment  of  the  temporal  fascia 
and  muscle.      It  begins  at  the  external  angular  process  of  the  frontal  bone  and  ends 


40  APPLIED    ANATOMY. 

at  the  asterion.  Its  anterior  third  is  well  marked,  but  as  it  crosses  the  coronal  suture 
it  fades  away  and  gradually  broadens  out,  its  upper  margin  being  called  the  superior 
and  its  lower  the  inferior  temporal  ridge.  The  superior  ridge  marks  the  attachment 
of  the  superficial  layer  of  the  temporal  fascia,  the  inferior,  the  deep  layer. 

External  Angular  Process. —  This  is  the  outer  extremity  of  the  frontal  bone, 
where  it  articulates  with  the  malar.  The  line  of  the  suture  can  be  distinctly  felt  in 
the  living. 

Malar  Tubercle. —  This  is  the  small  bony  projection  on  the  posterior  edge  of 
the  malar  bone,  1.25  to  2  cm.  (^'2  to  i^  in.)  below  the  frontomalar  suture. 

Stephanion. —  The  point  where  the  temporal  ridge  crosses  the  coronal  suture. 

TOPOGRAPHICAL  POINTS. 

Pre-auricular  Point. —  The  depression  in  front  of  the  ear  and  just  behind  the 
condyle  of  the  lower  jaw. 

Sylvian  Point. —  Where  the  anterior  ascending  and  anterior  horizontal  limbs 
come  off  from  the  posterior  horizontal  limb  of  the  fissure  of  Sylvius.  It  lies  4  cm. 
(i5/^  in.)  posterior  and  a  little  above  the  external  angular  process,  at  the  junction  of 
the  parietal,  sphenoid,  and  temporal  bones. 

Superior  Rolandic  Point. —  Where  the  upper  end  of  the  line  marking  the 
Rolandic  fissure  crosses  the  median  line. 

Inferior  Rolandic  Point. —  Where  the  lower  end  of  the  line  marking  the 
Rolandic  fissure  crosses  the  line  of  the  Sylvian  fissure. 

The  Lower  Level  of  the  Br.ain. 

The  lower  level  of  the  brain  is  marked  by  a  line  beginning  in  the  median  line 
I  cm.  (i  in.)  above  the  nasion,  thence  above  the  orbit  i  cm.  from  its  edge  to  the 
external  angular  process;  from  here  it  goes  to  the  middle  of  the  zygoma,  thence 
backward  along  its  upper  border,  above  the  auditory  meatus  and  along  the  supe- 
rior curved  line  to  the  inion  (occipital  protuberance). 

FISSURES    AND   CONVOLUTIONS. 

The  conformation  of  the  various  fissures  and  con\olutions  varies  so  much  within 
normal  limits  that  it  is  not  possible  to  outline  them  on  the  surface  of  the  scalp  or 
skull  with  absolute  exactness.  The  various  lines  which  are  laid  out  to  indicate  their 
course  are,  therefore,  only  appro.ximate,  but  they  are  sufficiently  accurate  for  opera- 
tive purposes.  To  allow  for  variations,  the  openings  made  are  usually  large,  and  the 
motor  areas  are  sometimes  identified  by  the  application  of  an  electrode. 

Fissure  of  Sylvius  ( fissura  cerebri  lateralis). — To  indicate  the  course  of 
the  Sylvian  fissure,  a  line  is  drawn  from  the  external  angular  process  of  the  frontal 
bone  through  a  point  2  cm.  (3/j^  in.)  below  the  most  prominent  part  of  the  parietal 
eminence  and  ending  1.5  cm.  (54  in.)  above  the  lambda.  The  main  portion  of  the 
Sylvian  fissure  begins  2  cm.  ( ^^  in.)  behind  the  angular  process;  2  cm.  farther  back 
or  42  mm.  ( i  i.-i  in. )  behind  the  angular  process  is  the  Sylvian  point,  where  the 
anterior  horizontal  and  anterior  ascending  limbs  are  given  off.  From  this  point  the 
posterior  horizontal  limb  passes  backward  to  2  cm.  ( -'^  in. )  below  the  highest  point 
of  the  parietal  eminence  and  then  curves  upward  and  backward  for  a  distance  of 
1.25  cm.  to  2  cm.  m  to  ^-^  in.). 

Central  Fissure,  or  Fissure  of  Rolando  (sulcus  centralis). — -The  line  of 
the  central  fissure  begins  at  the  upper  Rolandic  point,  1.5  cm.  (^g  in.  )  behind  the 
middle  of  a  sagittal  line  passing  from  the  glabella  to  the  inion.  It  then  passes 
down  and  forward  at  an  angle  of  approximately  70°  (67  J^,  Chiene)  toward  the 
middle  of  the  zygoma  (Le  Fort)  to  end  at  the  lower  Rolandic  point,  where  it  inter- 
sects the  Sylvian  line.  It  is  about  9  cm.  (3}^  in.)  long.  The  central  fissure  stops 
I  cm.  abo\'e  the  Sylvian  line  or  fissure. 

Parieto-occipital  Fissure  (fissura  parieto-occipitalis). — The  position  of 
this  fissure  is  quite  \'ariable,  an  average  being  1.5  cm.  (5-^  in.)  above  the  lambda,  and 
extending  1.25  cm.  (  j4  in.)  out  from  the  median  line.  It  is  about  6  cm.  (2j^  in.) 
above  the  inion  and  on  or  below  the  line  of  the  Sylvian  fissure. 


THE    BRAIN. 


41 


Subsidiary   Fissures   and   Coxvolutions. 

The  precentral  and  postcentral  sulci  are  about  15  mm.  (f  in.)  anterior 
and  posterior  to  the  fissure  of  Rolando. 

The  inferior  frontal  convolution  lies  between  the  line  of  the  fissure  of 
Sylvius  below  and  a  line  just  below  the  temporal  ridge  above. 

The  middle  frontal  convolution  lies  under  the  frontal  eminence,  and  occu- 


Litie  for  central  or 
Rolandic  fissure 
Precentral  sulc 


.Line  for  Sylvian  fissure 

Temporal  ridge 

Ascending  limb  of 
'Sylvian  fissure 

Anterior  horizontal  limb 
Main  portion  of 

Sylvian  fissure 

Glabella 

Nasion 


h\^}-> 


Fig.  50. — Seniidiagramraatic  view  of  head,  showing  relation  of  Rolandic  and  Sylvian  fissures  and  lines. 

pies  about  the  lower  two-thirds  of  the  distance  between  the  temporal  ridge  below 
and  the  midline  abo\'e. 

The  superior  frontal  convolution  covers  about  the  upper  one-third  of  the 
distance  from  the  median  line  above  to  the  temporal  ridge  below. 

The  superior  frontal  sulcus  passes  upward  from  the  supra-orbital  notch. 

The  inferior  frontal  sulcus  runs  just  below  the  temporal  ridge. 

The  first  or  superior  temporal  convolution  runs  along  the  lower  side  of 
the  fissure  of  Sylvius.      It  is  about  15  mm.   {f  in.)  wide. 

The  first  or  superior  temporal  sulcus  or  parallel  fissure  runs  parallel  to 
the  Sylvian  fissure  and  15  mm.  below. 

The  second  or  middle  temporal  convolution  is  wider  than  the  first  and  lies 
a  short  distance  abo\-e  the  le\el  of  the  base  of  the  skull. 

The  middle  temporal  sulcus  runs  close  above  the  zygoma. 

The  third  or  inferior  and  the  fourth  temporal  convolutions  He  on  the  base 
of  the  brain, separated  by  the  inferior  temporal  sulcus.  The  fourth  temporal  convo- 
lution has  on  its  inner  side  the  collateral  fissure  fsee  Fig.  42). 

The  interparietal  sulcus  (pars  horizontalis)  leaves  the  postcentral  sulcus 
near  its  middle  and  passes  upward  and  backward  to  a  point  opposite  the  lambda. 

The  supramarginal  convolution  surrounds  the  termination  of  the  fissure  of 
Sylvius  and  is,  therefore,  under  the  parietal  eminence. 


APPLIED    AXATO.MV 


The  angular  gyrus  surrounds  the  posterior  end  of  the  first  temporal  sulcus 
(parallel  fissure)  and  is,  therefore,  3  or  4  cm.  (l}^  to  ij^  in.)  posterior  to  the 
parietal  eminence. 

The  transverse  occipital  sulcus  is  a  continuation  of  the  interparietal  sulcus 
to  just  beyond  the  parieto-occipital  fissure. 

The  lateral  occipital  sulcus  lies  close  to  the  tentorium;  it  divides  the  occipi- 
tal lobe  into  superior  and  inferior  convolutions.  (Sometimes  these  two  sulci  divide 
the  lobe  into  three  convolutions,  superior,  middle,  and  inferior.) 

The  Fissures  in  Children. — In  childhood  the  fissure  of  Rolando  is  somewhat 
more  vertical  than  in  adults ;  the  fissure  of  Sylvius  has  its  point  of  division  a  little 
higher  and  runs  up  to  and  usually  above  and  in  front  of  the  parietal  eminence 
(Dana,  .1/ed.  Record,  Jan.  1889,  p.  29).  After  the  age  of  three  years,  the  relative- 
position  of  the  fissure  to  the  parietal  eminence  begins  to  approach  that  of  the  adult. 
(For  variations  due  to  age  see  Cunningham :  ' '  Contributions  to  the  Surface  Anatomy 
of  the  Cerebral  Hemispheres,"  1892.) 

The  objects  of  cerebral  topography  are  mainly  to  ascertain  in  case  of  injury  or  disease  of 
the  superficial  structures  what  parts  of  the  brain  beneatli  are  liable  to  be  invol\ed,  and  for  opera- 
tive procedures,  in  order  to  e.xpose  the  affected  areas. 
The  convolutions  and  sulci  are  so  variable  that  all 
guides  are  only  approximate.  In  order  to  overcome 
this  defect  and  provide  for  unusual  conditions,  the 
openings  in  the  skull  are  usually  made  quite  large. 
The  flaps  of  scalp  and  bone  may  e\en  embrace  the 
entire  parietal  bone  or  a  quarter  of  one  hemisphere. 
.\s  regards  the  various  points — the  upper  Rolandic 
point  is  generally  conceded  to  be  15  mm.  (^^  to  ;s  in.) 
posterior  to  the  midpoint  between  the  glabella  and 
inion.  The  angle  which  the  fissure  forms  with  the 
median  line  varies  from  64°  to  75°.  Cunningham 
gives  it  as  70°  and  Arthur  \V.  Hare  as  67°.  Chiene's 
method  of  finding  the  desired  angle  is  usually  accepted 
as  reliable.  He  takes  a  square  piece  of  paper  and 
folds  it  obliquely  from  corner  to  corner  making  45°, 
and  then  folds  it  a  second  time  making  22^2°.  The 
tH  o  being  added  together  give  67><°  as  the  angle  made 
by  the  fissure  of  Rolando  with  the  anterior  portion  of 
degrees.  "  the  longitudinal  fissure. 

The  pterion  was  placed  by  Broca  at  the  coronal  su- 
ture. This  is  15  mm.  ( 5  in. )  in  front  of  the  Sylvian  point.  In  several  formalin  hardened  brains,  we 
found  this  latter  to  be  at  the  posterior  angle  of  the  pterygoid  wing,  and  in  twenty  measured 
skulls  the  Sylvian  point  averaged  42  mm. 
(i.^s  in.)  behind  the  angular  process.  Reid 
placed  it  at  50  mm.  (2  in.) ,  which  we  think  too 
much.  Anderson  and  Makin  placed  it  at  i '/^  to 
2  in.  Thane  and  Godlee  placed  it  35  mm.  back 
and  12  mm.  up,  which  is  just  a  trifle  farther 
forward  than  we  have  located  it.  Landzert 
and  Heffler  gave  it  as  at  the  summit  of  union 
of  the  great  wing  of  the  sphenoid  with  the 
temporoparietal  suture,  as  we  ha\e  given  it. 
When  prolonged,  the  Sylvian  fissure  some- 
times crosses  the  median  line  1.5cm.  (5|  in.) 
above  the  parieto-occijiital  fissure,  but  more 
usually  we  have  found  it  to  be  close  to  the 
fissure,  which  agrees  with  Reid.  The  parieto- 
occipital fissure  has  been  located  by  some 
authors  near  the  lambda,  but  we  would  place  it 
1.5  cm.  (  5^  in.)  above.  We  believe  the  parie- 
tal eminence  to  be  a  fairly  reliable  guide  to  the 
posterior  extremity  of  the  fissure  of  Sylvius. 
jMe//iod  of  Anderson  and  Makin  for 
Locating  the  Fissures  of  the  Brain. — For  the  sake  of  comparison  the  following  method  of 
Wm.  Anderson  and  George  Henry  Makin  {Jour.  .4nat.  and  Phys.,  vol.  .xxiii,  18SS-89,  p.  455)  is 


THE    BRAIN. 


43 


given.  Draw  a  mid-  or  sagittal  line  from  opposite  the  highest  point  of  the  supra-orbital  arclies 
to  the  e.xternal  occipital  iirotiiberance.  From  the  midpoint  on  this  line  draw  another  to  the 
pre-auricular  point  at  the  level  of  the  upper  border  of  the  meatus.  This  is  the  frontal  line. 
From  the  most  prominent  point  of  the  external  angular  process  draw  a  line  to  tlie  junction  of 
the  middle  and  lower  thirds  of  the  frontal  line  and  prolong;  it  jyi  in.  beyond. 

The  Sylvian  fissure  begins  between  lYs  and  ij/,  in.  behind  the  angular  process  or  -j^r  of 
the  distance  between  that  point  and  the  frontal  line.  The  bifurcation  is  i}4  to  2  in.  behind  the 
angular  process  or  ^.j  of  the  distance  between  it  and  the  frontal  line,  the  fissure  then  runs  to  an 
equal  distance  behind  the  frontal  line,  and  up  for  yi  in.  parallel  to  the  frontal  line.  The  fissure 
of  Rolando  runs  from  a  point  Y^  in.  behind  the  midsagittal  point  to  one  %  of  an  inch  in  front  of 
the  intersection  of  the  frontal  line  and  line  of  the  Sylvian  fissure.  The  parieto-occipital  fissure 
is  ,\  of  the  distance  from  the  midsagittal  point  to  the  inion.  It  lies  near  the  ape.x  of  the  lamb- 
doid  suture. 

The  Lateral  Ventricles. — The  lateral  ventricles  sometimes  become  distended  by  serous  or 
purulent  effusions  or,  as  in  apoplexy,  by  blood.     In  order  to  tap  them  Keen  {"  Reference  Hand- 


Fissure  of  Rolando 


^m^> 


Middle  meningeal  artery,  posterior 
branch  ;  Inierior  horn  of  lateral  ven- 
tricle seen  beneath 


-Tapping  the  lateral  ^ 


;ntricles  and  trephining  for  cerebral  abscess.    Semidi; 
ng  relation  of  Rolandic  and  Sylvian  fissures  and  lines 


/  of  head .  show- 


book  of  the  Medical  Sciences,"  vol.  viii.,  p.  229)  has  given  three  points,  as  follows:  (i)  One- 
half  to  three-fourths  of  an  inch  (1.25  to  2  cm.)  on  either  side  of  the  median  line  and  one-third 
of  the  distance  from  the  glabella  to  the  upper  end  of  the  central  (Rolandic)  fissure.  This  is 
high  enougli  to  avoid  the  frontal  air-sinuses  and  is  in  advance  of  the  motor  area.  A  grooved 
director  is  lo  be  thrust  in  the  direction  of  the  inion.  The  ventricle  is  reached  at  a  depth  of  5  to 
6.5  cm.  {2  to  2'X  in.)  through  the  first  frontal  convolution.  (2)  Midway  between  the  inion 
and  upper  end  of  the  central  (Rolandic)  fissure  1.25  to  2  cm.  {yi  to  }(  in.)  from  the  median 
line.  The  director  is  to  be  thrust  toward  the  inner  end  of  the  supra-orbital  ridge  of  the  same 
side.  The  ventricle  will  be  reached  at  a  depth  of  5.5  to  7  cm.  (2%  to  2^  in.)  from  the  sur- 
face. (3)  Three  centimetres  {1%  in.)  behind  the  external  auditory  meatus  and  the  same  above 
Reid's  base  line  (from  the  lower  border  of  the  orbit  through  the  centre  of  the  external  auditory 
meatus).  The  director  is  to  be  thrust  toward  a  point  6.25  to  7. ,5  cm.  (2 "4  to  3  in.)  directly 
above  the  opposite  external  meatus.  The  ventricle  will  be  reached  5  to  5.75  cm.  (2  to  2 '4  in.) 
from  the  surface.  The  director  passes  through  the  second  temporal  convolution;  this  is  the 
preferred  method. 


44  APPLIED    ANATOMY. 

Spitzka  {Neicj  York  Med.  Jour.,  Feb.  2,  1901,  p.  177)  has  pointed  out  how  these  ventricles 
vary  in  shape,  and  has  given  the  surface  relations  in  two  brains.  T.  T.  Wilson  (Jour.  Anat.  and 
Phys.,  vol.  x.xviii,  1894,  pp.  22S-235)  has  described  and  figured  them  in  three  drawings.  Spitzka 
states  that  the  ventricles  will  hold  about  60  c.c.  of  liquid. 

Cerebral  Abscess. — About  one-half  of  the  abscesses  of  the  brain  occur  from  disease  of  the 
middle  ear,  and  they  are  located  in  the  temporosphenoidal  lobe,  in  the  cerebellum,  or  between 
the  dura  and  petrous  portion  of  the  temporal  bone.  The  remainder  are  caused  either  by  blows 
or  infection  carried  to  the  part  in  infectious  diseases.  They  may,  therefore,  occur  anywhere  in 
the  brain. 

W'hen  the  motor  areas  around  the  fissure  of  Rolando  are  involved,  the  location  of  the 
trouble  will  be  shown  by  spasm  or  paralysis  of  the  corresponding  muscles.  If  the  occipital  lobe 
is  affected  there  may  be  disturbance  of  sight,  as  hemiopia.  Involvement  of  the  frontal  lobes 
produces  mental  dulness,  and  if  of  the  third  left  frontal  gyrus,  or  Broca's  convolution  there  may 
be  impairment  of  speech.  Disease  of  the  middle  lobe  of  tire  cerebellum  may  be  accompanied 
by  a  staggering  gait.  In  many  cases  localization  symptoms  are  rare,  particularly  when  the 
abscess  is  small  and  located  in  the  temporosphenoidal,  parietal,  or  frontal  lobes  (see  chapter  on 
cerebral  localization). 

Trephining. — If  the  abscess  arises  from  middle-ear  disease,  it  is  customary  to  first  open 
the  mastoid  antrum  (see  chapter  on  ear)  and  then  by  removing  the  bone  above  to  explore  the 
surface  of  the  petrous  portion  of  the  temporal  bone.  To  e.xplore  the  temporal  lobe  an  opening 
may  be  made  2.5  cm.  (i  in. )  above  the  e.xternal  auditory  meatus  and  a  needle  passed  inward, 
forward,  and  a  little  downward. 

To  reach  the  cerebellum,  the  trephine  should  be  applied  5  to  7  cm.  (2  to  2  3/  in.)  behind 
the  external  meatus  and  well  below  the  superior  curved  line.  The  bone  at  this  point  is  apt  to 
be  thin  and  care  is  to  be  exercised  not  to  wound  the  membranes.  The  place  of  trephining  in 
abscesses  from  other  causes  is  to  be  decided  by  the  localizing  symptoms. 

THE   FACE. 

The  face  may  be  divided  into  the  regions  of  the  forehead,  temples,  ears,  eyes, 
nose,  viotith,  cheek,  and  upper  and  Imver  jaws.  The  regions  of  the  eyes,  ears,  nose, 
and  mouth  will  be  considered  separately.  Owing  to  the  face  being  that  part  of  the 
body  most  open  to  scrutiny  and  most  difificult  of  concealment,  deformities  and  dis- 
figurements of  it,  resulting  from  injury  or  disease, — to  both  of  whicli  it  is  prone, — 
assume  a  greater  importance  tlian  the  same  troubles  elsewhere.  Therefore,  the 
anatomy  of  the  part  should  be  studied  with  regard  to  the  treatment  of  its  various 
affections  from  a  cosmetic  as  well  as  from  a  curative  point  of  view.  What  is  usually 
regarded  as  constituting  the  face  embraces  the  anterior  half  of  the  head  as  viewed 
from  the  front. 

The  Bones.  —  The  bones  of  the  head  have  been  divided  into  those  of  the 
cranium  and  those  of  the  face.  The  bones  of  the  cranium  are  eight  in  number,  viz. : 
the  frontal,  occipital,  two  temporals,  two  parietals,  the  sphenoid,  and  ethmoid.  The 
bones  of  the  face  are  fourteen  in  number,  of  which  twelve  are  in  pairs,  viz:  superior 
ma.xillary,  malar,  nasal,  palate,  lachrymal,  and  inferior  turbinated  bones — the  vomer 
and  inferior  ma.xilla  or  mandible  are  the  two  single  bones. 

From  this  it  will  be  seen  that  the  bony  framework  of  the  face  embraces  some  of 
the  bones  of  the  skull,  as  well  as  those  of  the  face  proper;  thus,  the  region  of  the 
forehead  is  formed  by  the  frontal  bone,  the  temporal  region  is  formed  by  the  frontal, 
parietal,  sphenoid,  and  temporal  bones,  all  belonging  to  the  cranium,  and  so  on. 
The  palate  bones  are  called  face  bones,  yet  they  are  placed  deep  in  the  region  of  the 
\nouth  and  nose. 

The  Soft  Parts. — The  soft  parts  are  likewise  of  importance.  The  skin,  thin  in 
some  parts,  thick  in  others,  is  in  many  places  loosely  attached  and  has  inserted  in  it 
the  muscles  of  expression.      It  is  frequently  the  seat  of  disease,  particularly  of  cancer. 

On  each  side  of  the  face  are  the  parotid  glands,  often  the  site  of  inflammations. 

The  blood-vessels,  both  arteries  and  veins,  particularly  the  former,  are  very 
numerous  and  gi\-e  special  characters  to  wounds  and  diseases  of  the  face. 

The  nerves  are  abundant  and  complex.  They  are,  with  the  exception  of  the 
auricularis  magnus,  which  comes  from  the  second  and  third  cervical,  and  to  a 
slight  extent  the  occipitalis  minor  from  the  second  cervical,  all  derived  from  the 
cranial  nerves  and  are  both  motor  and  sensory.      The  paralyses  and  neuralgias  which 


THE   FACE. 


45 


afEect  them  are  among  the  most  distressing   and  disfiguring   of  any  in  the  body, 
wounds  of  the  face  producing  paralysis  of  the  muscles  of  expression. 

The  relatively  small  size  of  the  face  in  relation  to  the  cranium  in  the  child  as 
compared  to  that  of  the  adult  has  already  been  alluded  to  (see  page  8).  The 
reasons  for  this  are  e-\'ident:  dentition  must  be  complete  to  insure  the  proper 
development  of  the  jaws;  the  use  of  the  special  senses  and  the  expression  of  the 
emotions  cause  the  facial  muscles  to  develop,  and  this  in  turn  causes  the  bones  to 
which  they  are  attached  to  become  more  rugged  in  outline  and  larger  in  size.  In 
old  age,  as  the  teeth  are  lost,  the  jaws  are  diminished  in  size  by  absorption  of  their 
alveolar  processes. 

THE    FRONTAL    REGION. 

The  frontal  region  embraces  that  part  of  the  face  above  the  eyes  and  nose  in 
front  and  anterior  to  the  temples  at  the  sides. 

The  Frontal  Suture. — The  frontal  bone  develops  from  two  centres  of  ossifi- 
cation, one  on  each  side.  These  unite  in  the  median  line  to  form  the  frontal  suture 
which  joins  the  anterior  fontanelle  and 
is  closed  about  the  same  time,  within  the 
age  of  two  years.  The  suture  occa- 
sionally persists  through  life  and  some- 
times the  line  of  jvuiction  can  be  felt  in 
the  li\'ing;  it  should  not  be  mistaken 
for  fracture. 

The  frontal  eminences  in  the 
child  are  particularly  prominent,  the 
forehead  projecting  bej^ond  the  edge  of 
the  orbit.  This  makes  it  difficult  to 
apply  a  bandage  securely  to  the  head 
in  children  unless  it  is  twisted  to  draw 
in  its  sides. 

The  superciliary  ridges  are 
about  a  centimetre  above  the  edge  of 
the  orbit  over  its  inner  half.  Aided  by 
the  hair  of  the  eyebrows  they  serve 
to  divert  the  sweat  to  the  sides,  as 
pointed  out  by  Humphry.  They  are 
best  developed  in  the  adult  male. 
Directly  between  them  in  the  median 

line  on  a  level  with  the  upper  edge  of  the  orbit  is  a  depression  called  the  glabella. 
It  is  the  anterior  point  from  which  measurements  are  taken  in  cerebral  topography. 

Frontal  Sinuses. — Beneath  the  superciliary  ridges  are  the  frontal  air-sinuses, 
but  the  size  of  the  sinuses  is  not  necessarily  proportional  to  that  of  the  ridges;  they 
may  extend  quite  far  back  over  the  orbit.  Fractures  of  the  outer  wall  of  these 
sinuses  not  infrequently  occur  without  the  inner  table  being  injured.  A  septum 
separates  one  sinus  from  the  other,  not  always  in  the  median  line.  The  lining- 
membrane  of  these  sinuses  is  often  inflamed  and  suppurates,  discharging  pus  into  the 
nose.      Tumors  also  grow  in  them. 

Margins  of  the  Orbit. — At  the  upper  and  outer  margin  of  the  orbit  is  the 
external  angular  process  of  the  frontal  bone.  The  line  of  junction  or  suture  between 
it  and  the  malar  bone  can  be  distinctly  felt  in  the  living  both  on  the  side  of  the  orbit 
and  on  the  side  toward  the  temple.  This  is  an  important  landmark  in  cerebral 
topograph)^,  as  it  is  used  to  locate  the  fissure  of  Sylvius  and  also  the  middle  menin- 
geal artery.  On  the  upper  margin  of  the  orbit  at  about  the  junction  of  its  middle 
and  inner  thirds  is  the  supra-orbital  notch.  This  can  usually  be  readily  felt  through 
the  skin.  Sometimes  it  is  a  complete  foramen  instead  of  simply  a  notch.  It  is  then 
to  be  located  by  feeling  on  the  orbital  surface  just  behind  the  edge.  It  transmits 
the  supra-orbital  nerve  and  artery. 

The  supra-orbital  nerve,  a  branch  of  the  ophthalmic  division  of  the  fifth  nerve, 
is  sometimes  the  seat  of  neuralgia,  for  which  resection  of  the  nerve  is  performed. 


Fig.  54. — Frontal  region  of  a  child's  skull. 


46  APPLIED    ANATOMY. 

The  pain  is  felt  above  the  orbit  radiating  from  the  supra-orbital  notch,  sometimes  as 
far  up  as  the  vertex.  Pain  is  also  felt  on  pressure  over  the  supra-orbital  notch.  If 
the  entire  ophthalmic  branch  of  the  fifth  nerve  is  affected,  pain  is  felt  in  the  eyeball 
and  clown  the  side  of  the  nose.  The  incision  in  operating  may  be  made  at  the 
lower  border  of  the  eyebrow,  its  centre  being  over  the  notch.  If  the  notch  is  not 
readily  felt  on  the  edge  of  the  bony  orbit  at  the  junction  of  the  inner  and  middle 
thirds,  it  can  be  detected  by  feeling  with  the  tip  of  the  finger  on  the  orbital  surface. 
The  incision  is  made  through  the  fibres  of  the  orbicularis  palpebrarum,  corrugator 
supercilii,  and  frontalis  muscles,  then  through  the  palpebral  ligament  immediately 
below  the  bony  edge  of  the  orbit,  and  the  orbital  fat  separated  with  forceps;  the 
nerve  is  then  caught  with  a  hook  before  it  enters  the  notch,  and  brought  up 
and  removed.      Considerable   ecchymosis   may  follow  this  operation   if  the  accom- 


FiG.  55. — Supra-orbital 


panying  artery  is  divided.  Operations  on  the  ophthalmic  division  of  the  fifth  ner\'e 
have  usually  been  done  in  connection  with  removal  of  the  Gasserian  ganglion,  the 
other  branches  being  also  involved. 

Nasion. —  About  a  centimetre  below  the  glabella,  in  the  adult  skull,  is  the 
nasion,  or  line  of  junction  of  the  frontal  and  nasal  bones.  It  is  along  this  frontonasal 
suture,  to  one  side  of  the  median  line,  that  an  anterior  menina^-ocele  is  apt  to  show 
itself. 

The  internal  angular  process  of  the  frontal  bone  articulates  with  the  nasal 
process  of  the  superior  maxilla  and  the  lachrymal  bones.  The  line  of  suture  is 
continuous  with  the  nasion  in  front  and  the  upper  edge  of  the  ethmoid  behind. 
Pus  originating  in  the  ethmoidal  cells,  frontal  sinuses,  and  lachr}rmal  apparatus  is  apt 
to  point  at  this  locality.      The  frontal  bone  is  a  favorite  seat  of  exostoses. 

THE   TEMPORAL    REGION. 

The  region  of  the  temple  is  on  the  side  of  the  head  as  far  forward  as  the  eye 
and  as  low  as  the  zygoma  and  infratemporal  crest.  The  floor  of  the  temporal  fossa 
is  formed  by  the  posterior  portion  of  the  frontal  and  anterior  portion  of  the  parietal 
bones  as  high  as  the  temporal  ridge,  the  outer  surface  of  the  greater  wing  of  the 
sphenoid,  and  the  squamous  portion  of  the  temporal  bone.  These  four  bones  meet 
to  form  the  region  of  the  pterion  (see  p.  39  and  42).  The  anterior  edge  of  the 
temporal  bone  overlaps  and  is  superficial  to  the  posterior  edge  of  the  sphenoid.    The 


THE   FACE. 


47 


anterior  edge  of  the  parietal  overlies  the  posterior  edge  of  the  frontal.  The  upper 
edges  of  the  temporal  and  sphenoid  overlap  the  lower  edges  of  the  frontal  and 
parietal  bones.  That  the  temporal  region  of  the  skull  is  distinctly  weaker  than  other 
regions  is  due  to  the  thinness  of  the  bones,  and  the  reason  that  fractures  here  are 
e.xceptionally  dangerous  is  on  account  of  the  middle  meningeal  artery  running 
through  a  canal  in  the  bone  in  this  region;  so  that  in  cases  of  fracture  the  artery 
is  torn  and  hemorrhage  occurs  above  the  dura,  which  causes  compression  of  the 
brain  (Fig.  56). 

The  infratemporal  crest  (crista  infratemporalis)  or  pterygoid  ridge  sep- 
arates the  temporal  region  abo\e  from  the  pterygoid  region  below.  It  is  an  important 
landmark  in  operating  on  the  Gasserian  ganglion. 

A  spot  two  centimetres  behind  the  e.xternal  angular  process  and  slightly  abo\'e 
its  level  marks  the  anterior  extremity  of  the  fissure  of  Sylvius.      In  trephining  in  the 


Fig.  56. — Frontal  and  temporal  regi' 


temporal  region  no  diploe  is  found  in  the  bones,  so  that  extreme  care  is  necessary 
to  avoid  wounding  the  dura  mater.  The  trephine  may  be  placed  4  cm.  (ili  in.) 
behind  the  e.xternal  angular  process  and  4.5  cm.  (i?4^  in.)  above  the  zygoma  to  strike 
the  middle  meningeal  artery.  This  will  be  level  with  or  a  little  above  the  highest 
part  of  tlie  edge  of  the  orbit. 

Temporal  Fascia. — This  is  the  dense  fascia  covering  the  temporal  muscle;  it 
is  formed  as  follows:  The  pericranium  as  it  comes  down  from  the  vault  of  the  skull 
and  reaches  the  temporal  ridge  passes  under  and  gives  attachment  to  the  temporal 
muscle.  The  temporal  fascia  consists  of  two  distinct  sheets  of  fascia,  the  superficial 
one  from  the  superior  temporal  ridge  being  attached  to  the  zygoma  below  and  to  the 
malar  bone  in  front;  the  deeper  layer  from  the  inferior  temporal  ridge  covers  the 
temporal  muscle,  and  a  short  distance  above  the  zygoma  divides  into  two  layers, 
one  of  which  is  attached  to  the  outer  edge,  and  the  other  to  its  inner  edge.  The 
upper  or  superficial  layer  of  the  temporal  fascia  leaves  the  bone  at  the  superior  tem- 
poral ridge  and  is  attached  below  to  the  top  of  the  zygoma,  blending  near  the  bone 
with  the  layer  beneath.  This  is  a  distinct  layer  though  not  always  readily  demon- 
strable in  dissections.  Between  the  layers  above  the  zygoma  is  some  fat  and  the 
orbital  branch  of  the  middle  temporal  artery.  Anteriorly  the  temporal  fascia  is 
attached  to  the  posterior  border  of  the  malar  bone  and  the  temporal  ridge  of  the 
frontal.      The  temporal  fascia  is  tough  and  dense  and  gives  attachment  by  its  under 


48 


APPLIED   ANATOMY. 


Galea  aponeuroti 


Temporal  fascia 
superficial  lay 


surface  to  the  temporal  muscle.  Abscess  occurring  under  the  temporal  fascia,  there- 
fore, does  not  tend  to  come  to  the  surface,  but  sinks  downward.  It  is  prevented 
from  making  its  e.xit  on  the  face  below  the  zygoma  by  the  parotid  gland  and 
masseter  muscle,  so  it  passes  inward  to  the  pterygoid  region  and  may  point  in  the 
throat  or  go  down  into  the  neck. 

The  occipitofrontal  aponeurosis,  or  galea  apo neurotica  as  it  approaches  the 
side  of  the  head  becomes  thinner  and  passes  down   to  insert  into  the  top   of  the 

zygoma  so  that  in  the  temporal 
region  the  layers  are  as  follows: 
Skin,  superficial  fascia,  galea 
apoiieurotica,  two  layers  of 
the  temporal  fascia,  temporal 
muscle,  an  indistinct  perios- 
teum, and  bone.  Immediately 
abo\'e  the  zygoma  we  ha\'e  the 
deep  layer  of  the  temporal  fascia 
dividing  instead  of  a  single 
layer  as  is  the  case  higher  up. 
The  temporal  fossa  contains 
considerable  fat  which  dis- 
appears in  serious  illnesses. 
Disfiguring  depressions  are  also 
left  in  this  region  after  opera- 
tions involving  the  temporal 
muscle. 

The  temporal  artery  be- 
gins opposite  the  neck  of  the 
lower  jaw,  then  passes  over  the 
temporoma.\illary  articulation, 
lying  on  its  capsule,  thence  over 
the  zygoma  about  a  centimetre 
in  front  of  the  ear.  It  lies  on 
the  temporal  fascia  and  about 
4  cm.  above  the  zygoma  divides 
into  an  anterior  and  posterior 
branch.  The  course  of  the 
temporal  artery  and  its  anterior 
branch  is  usually  quite  conspic- 
uous in  old  people  and  affords 
a  ready  means  of  ascertaining 
whether  or  not  the  arteries 
possess  the  calcareous  deposits 
characteristic  of  atheroma.  The 
location  of  the  artery  in  front 
of  the  ear  should  be  remem- 
bered, as  the  pulse  is  readih' 
felt  there  in  the  administra- 
tion of  ansesthetics.  In  certain 
angiomas  of  the  scalp  the 
blood  suppl}'  may  be  dimin- 
ished by  ligating  the  vessel  at 
that  point. 

The  temporal  muscle  receives  blood  from  the  middle  temporal  artery  which  comes 
from  the  temporal  and  perforates  the  temporal  fascia  just  above  the  zygoma,  and  from 
the  anterior  and  posterior  temporal  branches  of  the  internal  maxillary.  The  tem- 
poral fossa  is  frequently  the  seat  of  operations  to  e.xpose  the  Gasserian  ganglion  and 
the  bleeding  from  these  various  temporal  arteries  contributes  to  their  gravity.  The 
auriculotemporal  nerve  lies  slightly  posterior  to  the  artery  and  the  vein  in  front  of  it. 
They  are  not  important. 


■ision  of  deep  lay 
of  temporal  fasc 


Orbital  branch  of 
temporal  arter\' 


verse  coronal  section  i 


THE  FACE. 


49 


THE  REGION  OF  THE  CHEEK. 

In  this  region  we  may  include  the  parts  limited  above  by  the  zygoma,  in  front 
by  the  eye,  nose,  and  mouth,  below  by  the  lower  edge  of  the  lower  jaw,  and  behind 
by  the  ear.  The  soft  parts  of  the  cheek  are  supported  by  the  malar  and  superior 
and  inferior  maxillary  bones.  Between  the  skin  and  the  buccinator  muscle,  the 
hollow  beneath  and  in  front  of  the  malar  bone  and  masseter  muscle  is  filled  with  fat, 
sometimes  called  the  sucking  pad  or  cushion.  In  disease  this  fat  disappears,  hence 
the  hollow  cheek  of  invalids.  The  muscles  of  expression  are  superficial  to  this  fat 
and  have  their  insertion  in  the  skin.  Swelling  occurs  readily  from  contusions  and 
inflammations  because  the  tissues  of  the  cheek  are  lax.  Inflammations  may  either 
start  in  the  skin,  which  is  quite  prone  to  disease,  or  may  be  the  result  of  inflammation 
of  some  surrounding  structure,  as  the  parotid  gland,  the  roots  of  the  teeth,  the 
lachrymal  sac,  eyelids,  etc. 

The  skin  of  the  cheek  contains  numerous  sebaceous  and  sweat  glands.  It  is  a 
favorite  site  for  the  pustular  eruptions  of  infancy  and  childhood,  the  acne  of  youth, 


Angul; 
Lateral  nasal 


Nasal  branch  of  ophthalmic 
Frontal  branch  of  ophthaln 


Superior  coronary 
Inferior  coronary  ^^__/''^ 
Inferior  labial. 


Facial  artery 


Facial  ^ 
Fig.  ■■ 


-The  facial  artery  and  its  branches. 


and  the  non-malignant  as  well  as  the  cancerous  ulcers  of  the  aged.  It  is  also  the 
seat  of  7ioma  or  cancriim  oi-is.  This  starts  on  the  mouth  surface  as  a  gangrenous 
stomatitis  and  implicates  the  cheek,  causing  death  or  great  disfigurement  owing 
to  the  loss  of  cheek  substance.  Facial  carbuncle  or  malignant  pustule  occurs  on  the 
cheek,  or  sometimes  on  the  lips.      It  is  very  fatal. 

Wounds  and  contusions  of  the  cheeks  are  common,  and,  as  the  blood  supplv  is 
abundant,  bleeding  is  free  and  healing  prompt.  On  account  of  the  insertion  of 
the  muscles  into  the  skin,  gaping  is  quite  marked. 

The  malar  bone  is  the  most  prominent  bone  of  the  cheek.  It  is  such  a 
strong  bone  and  so  strongly  supported  that  fracture  of  it,  as  well  as  that  of  the 
zygoma,  is  rare.  It  may  be  broken  by  direct  violence,  as  being  hit  with  a  stone,  etc. 
It  is  extremely  difficult  and  often  impossible  to  restore  the  fractured  parts  to  their 
original  level,  therefore  deformity  following  fracture  is  of  frequent  occurrence. 
The  fracture  may  involve  the  margin  of  the  orbit  and  cause  an  efTusion  of  blood 
into  the  orbit,  pushing  the  eye  forward.  A  fracture  of  the  zygoma,  if  \'ery  much 
depressed,  may  interfere  with  the  use  of  the  temporal  muscle  below,  necessitating 
operation.      This  occurrence  is,  however,  rare. 


50 


APPLIED   ANATOMY. 


The  facial  artery  runs  upward  and  inward,  from  a  couple  of  centimetres  in  front 
of  the  angle  of  the  jaw,  along  the  anterior  border  of  the  masseter  muscle  to  the  angle 
of  the  mouth,  and  thence  to  the  inner  canthus  of  the  eye.  The  anterior  edge  of  the 
masseter  muscle  can  usually  be  distinctly  felt  beneath  the  skin.  At  this  point  the 
vessel  can  be  ligated  or  temporarily  compressed  by  passing  a  pin  beneath  it  and 
winding  a  silk  ligature  above  it,  around  the  ends  of  the  pin.  This  procedure  is 
desirable  in  some  operations  on  the  cheek,  as  angiomas  frequently  affect  this  region. 
If  the  facial  arter}'  is  ligated,  the  blood  supply  comes  from  the  superior  and  inferior 
coronary  arteries  of  the  opposite  side;  the  nasal  branch  of  the  ophthalmic,  anasto- 
mosing with  the  angular;  the  transverse  facial  below  the  zygoma,  from  the  temporal; 
the  infra-orbital,  a  branch  of  the  internal  ma.xillary  ;  and  to  a  slight  extent  from  the 
inferior  labial  and  others  still  less  important  (Fig.  58). 

The  internal  maxillary  artery,  one  of  the  terminal  branches  of  the  external 
carotid,  arises  in  the  parotid  gland  opposite  the  neck  of  the  lower  jaw.  This  is  just 
below  and  behind  the  articulation,  which  can  be  readily  felt  through  the  skin.      It 


Muscular  branches 


Infra-orbital 


uperioralveolar 
(posterior  dental) 


Superficial  temporal 

artery 

Spbenomaiidibular 

ligament' 

Middle  meninq-eE 


External  carotid' 


Inferior  alveolar  (dental) 


hlG.  59. —  Ihe  internal  maxillary  artery. 

passes  between  the  bone  and  the  sphenomandibular  (long  internal  lateral)  ligament, 
then  between  the  two  pterygoid  muscles  or  between  the  two  heads  of  the  external 
pterygoid  muscle  to  the  posterior  surface  of  the  superior  maxillary  bone  in  the 
sphenomaxillary  fossa.  The  branches  of  its  first  part,  where  it  is  behiiid  the  neck  of 
the  jaw,  are  the  deep  auricular,  tympanic,  middle  and  small  meningeal,  and  inferior 
alveolar  {dental).  The  branches  of  its  second  part,  as  it  passes  between  the  ptery- 
goid muscles,  are  all  muscular  :  they  are  the  masseteric,  pterygoid,  anterior  and 
posterior  deep  temporal,  and  the  buccal.  The  branches  of  the  third  portion  of  the 
artery,  in  the  sphenomaxillary  fossa,  2.re  the  posterior  dental,  infra-orbital,  descending 
palatine.  Vidian,  pterygopalatine,  and  spheno-  or  nasopalatine. 

The  main  trunk  of  the  internal  maxillary  artery  is  not  often  involved  either  by 
injury  or  operations.  The  various  branches  are,  however,  of  considerable  impor- 
tance, as  they  supply  parts  which  are  often  the  site  of  operative  measures.  The 
importance  of  the  middle  meningeal  artery  in  reference  to  fractures  of  the  skull  has 
already  been  pointed  out.  The  inferior  alveolar  gives  rise  to  troublesome  hemorrhage 
when  the  lower  jaw  is  operated  on.  The  deep  temporal  branches  bleed  freely  when 
the  temporal  muscle  is  incised  in  operating  on  the  Gasserian  ganglion.  The  infra- 
orbital is  involved  in  operating  on  the  infra-orbital  nerve.  The  posterior  or  descending 
palatine  branch  descends  in  the  posterior  palatine  canal,  in  company  with  a  branch 


THE  FACE. 


51 


from  Meckel's  ganglion,  to  emerge  on  the  roof  of  the  mouth  at  the  posterior  palatine 
foramen.      It  causes  free  hemorrhage  in  operating  on  cleft  palate. 

The  Vidian  and  pterygopalatine  branches  supply  mostly  the  roof  of  the  pharynx; 
they  bleed  when  adenoids  are  removed.  The  descending  and  sphenopalatine  sup- 
ply the  upper  part  of  the  tonsil  with  blood  and  may  give  rise  to  serious  hemorrhage 
in  the  removal  of  the  tonsils.  In  operating  on  Meckel's  ganglion,  bleeding  from 
these  vessels  is  free.  The  nasopalatine  runs  forward  in  the  nose  in  the  groove  on 
the  vomer.  It  is  often  the  cause  of  serious  nasal  hemorrhages  in  operations  on  the 
septum.  In  removal  of  the  upper  jaw,  bleeding  occurs  from  many  of  the  branches 
of  the  internal  maxillary,  but  it  is  hardly  so  free  as  might  be  expected,  especially  if 
the  external  carotid  has  been  previously  ligated. 


PAROTID  GLAND. 

The  parotid  gland  lies  on  the  cheek,  behind  the  jaw  and  below  the  ear.  The 
limits  (Fig.  60)  of  the  gland  are  important  because  suppuration  may  occur  in  any  por- 
tion of  its  structure.      Its  extent  is  as  follows  :    above  to  the  zygoma,  lying  below  its 

Superficial  temporal  artery 
Transverse  facial  artery  ' 

Parotid  duct  ' 


Submaxillary  gland 


Facial  artery  e 
Fig.  60. — Parotid  gland  and  structures  of  the  side  of  the  face. 

posterior  two-thirds;  posteriorly,  to  the  external  auditory  canal,  the  mastoid  process, 
and  digastric  and  sternomastoid  muscles  ;  below  to  a  line  joining  the  angle  of  the  jaw 
and  mastoid  process  ;  and  in  front  about  half  the  width  of  the  masseter  muscle. 
This  latter  is,  however,  quite  variable. 

The  parotid  duct,  also  called  Stenson' s  duct,  leaves  the  upper  anterior  portion 
of  the  gland  about  a  centimetre  below  the  zygoma  and  runs  on  a  line  joining  the 
lower  edge  of  the  cartilaginous  portion  of  the  ear  with  the  middle  of  the  upper  lip. 
It  opens  on  a  papilla  on  the  inside  of  the  cheek  opposite  the  second  upper  molar 
tooth.  This  papilla  can  readily  be  seen  and  a  fine  probe  can  be  inserted  from  the 
mouth  into  the  duct;  thus  the  presence  of  a  calculus  may  be  detected.  In  operating 
on  the  cheek  the  line  of  this  duct  must  be  borne  in  mind,  as  wounding  it  may  cause 
a  salivary  fistula.  Wounds  of  the  lobules  of  the  gland  are  not  nearly  so  liable  to 
result  in  fistula  as  those  of  the  duct  itself. 


52  APPLIED    ANATOMY. 

Parotid  Fascia. — The  gland  is  covered  by  the  parotid  fascia.  This  fascia  is 
moderately  dense  and  is  continuous  with  the  fascia  separating  the  lobules  of  the  gland. 
Above  it  is  attached  to  the  zygoma  ;  in  front  it  is  continuous  with  the  masseteric 
fascia  over  the  masseter  muscle  ;  and  below  and  posteriorly  it  is  continuous  with  the 
deep  fascia  of  the  neck.  It  stretches  from  the  angle  of  the  jaw  to  the  sternomastoid 
muscle  and  somewhat  deeper  to  the  styloid  process  ;  the  band  running  from  the 
styloid  process  to  the  lower  jaw  is  called  the  stylomandibular  ligament.  From 
thence  it  is  continued  over  the  internal  carotid  artery  and  the  upper  surface  of  the 
internal  pterygoid  muscle. 

Lobes  of  the  Parotid  Gland. — The  gland  has  e.xtentions  in  various  directions 
(Fig.  6i).  A  prolongation  behind  the  articulation  of  the  lower  jaw,  into  the  posterior 
portion  of  the  glenoid  cavity  immediately  in  front  of  the  e.xternal  auditory  canal,  is  . 
called  the  glenoid  lobe.  Another  extension  winds  around  the  posterior  edge  of  the 
lower  jaw  on  the  lower  surface  of  the  internal  pterygoid  muscle  and  is  called  \h&  ptery- 


Pterygoid  lobe 
Digastric  muscle  \  \ 

Carotid  lobe        External  carotid  arteiA' 

Fig.  6i. — The  lobes  of  the  parotid  gland. 

goid  lobe.  A  prolongation  inward,  passing  between  the  external  carotid  on  the  outside 
and  the  styloid  process  and  the  internal  carotid  artery  on  the  inside,  is  called  the 
carotid  lobe.  A  separate  portion  of  the  gland,  sometimes  quite  detached,  lies  at  its 
upper  anterior  portion  between  the  zygoma  and  the  duct  of  Stenson ;  it  is  called  the 
socia  parotidis. 

Vessels  and  Nerves  Traversing  the  Gland. —  The  external  carotid  artery 
enters  the  gland  to  di\'ide  opposite  the  neck  of  the  lower  jaw  into  the  temporal  and 
internal  maxillary.  The  temporal,  before  it  leaves  the  gland,  gives  off  the  trans- 
verse facial  artery  which  runs  forward  on  the  face  between  the  zygoma  and  parotid 
duct.  It  is  usually  small  but  at  times  may  be  quite  large  and  even  go  over  to  the 
angle  of  the  mouth  and  form  the  two  coronary  arteries  (as  shown  in  M'CleUan's 
"Regional  Anatomy"  ).  The  temporal  vein,  as  it  descends  into  the  gland,  is  joined 
by  the  internal  maxillary  vein  to  form  the  temporomaxillary  vein,  which,  after  it 
receives  the  posterior  auricular  vein,  goes  to  form  the  external  jugular. 

The  facial  nerve  emerges  from  behind  the  jaw  just  below  the  lobe  of  the  ear  and 
divides  into  its  various  branches  while  still  in  the  gland.  There  is  usually  a  large 
branch  passing  parallel  to  the  duct  of  Stenson  and  below  it.  The  auriculotemporal 
nerve  follows  the  temporal  artery,  emerging  from  the  gland  a  little  posterior  to  the 
artery.  It  is  not  of  much  surgical  moment.  The  auricularis  magnus  from  the  second 
and  third  cervical  supplies  the  skin  over  the  gland. 


THE  FACE. 


53 


Lymphatic  nodes  are  found  both  on  the  gland  and  in  its  substance.  These  may 
be  invol\-ed  in  general  disease  of  the  cer\-ical  lymphatics. 

Affections  of  the  Parotid  Gland. — ^The  duct  may  be  affected  with  calculus, 
as  already  mentioned.  As  the  opening  of  the  duct  at  the  papilla  is  smaller  than  the 
lumen  of  the  canal  farther  back,  calculi  are  apt  to  lodge  close  to  the  anterior  extrem- 
ity. They  are,  therefore,  readily  felt  and  removed  by  incision  on  the  inside  of  the 
mouth.     The  gland  proper  is  subject  to  inflammations  and  tumors. 

Simple  parotiditis  or  mumps  really  is  an  infectious  inflammation,  nevertheless,  it 
rarely  suppurates.  Suppurative  parotiditis  may  occur  from  infected  wounds  or  arise 
in  the  course  of  the  eruptive  fevers,  etc.  In  inflammation  of  the  gland,  pain  and 
swelling  are  important  symptoms.  The  pain,  which  is  considerable,  is  not  due  so 
much  to  the  so-called  dense  parotid  fascia  covering  the  gland,  for  this  is  only 
moderately  thick,  as  it  is  to  the  fact  that  the  gland  is  of  a  racemose  type  and  the 


/Temporal  artery 

■otid  duct 


Fig.  62.— Structun 


'ith  the  parotid  gland. 


fibrous  septa  between  the  lobules  are  abundant  and  prevent  free  expansion  of  the 
contained  lobules.  E.xpansion  is  also  hindered  by  the  peculiar  location  of  the  various 
parts  of  the  gland.  Swelling  of  the  glenoid  lobe  produces  pain  in  the  ear  and  also  in 
the  temporomaxillary  articulation.  Swelling  of  the  carotid  and  pterygoid  lobes 
causes  pain  and  fulness  in  the  throat.  Opening  the  lower  jaw  reduces  the  space 
posterior  to  it  in  which  the  gland  lies  and  pinches  it  against  the  bony  meatus  and 
mastoid  process,  so  that  it  is  impossible  to  open  the  javv^  widely. 

If  suppuration  occurs  it  is  liable  to  progress  from  one  lobule  to  another;  when 
this  is  the  case  comparatively  small  abscesses  may  appear  in  different  parts  of  the 
gland  with  unaffected  tissue  between  them.  As  an  abscess  heals  in  one  lobule,  sup- 
puration is  apt  to  occur  in  another,  consequently  the  disease  may  persist  for  a  long 
time.  More  rarely  in  the  course  of  or  following  infectious  diseases,  particularly  in 
debilitated  patients,  considerable  portions  of  the  gland  may  slough.  This  form  is  apt 
to  be  fatal.  If  the  suppurating  focus  is  confined  to  lobules  which  are  deeply  placed, 
the  diagnosis  may  be  obscure  because  it  is  difficult  to  localize  the  affected  spot.  If, 
however,  it  is  near  the  surface  of  the  gland,  the  pus  does  not  tend  to  extend  sidewaj's, 
the  fibrous  septa  prevent  this,  but  it  tends  to  work  its  way  up  and  perforate  the  skin. 
If  the  glenoid  lobe  is  affected,  the  pus  may  find  an  exit  through  the  external  auditory 
meatus  or  even  involve  the  temporomaxillary  joint.     If  the  carotid  or  pterygoid  lobes 


54 


APPLIED    ANATOMY. 


are  affected,  the  pus  may  go  between  the  pterygoid  muscles,  or  around  the  internal 
carotid  artery  and  project  and  open  into  the  pharynx.  It  may  also  break  into  the 
carotid  artery  or  jugular  vein,  or  perforate  through  the  fascia  below  and  go  down 
the  neck.      Large  abscesses  and  sloughs  may  be  followed  b_v  a  parotid  fistula. 

Lines  of  Incision  fo?-  Abscess. — The  manner  of  opening  a  parotid  abscess 
depends  on  its  location  and  size.  If  it  is  desired  to  open  an  abscess  anterior  to  a 
point  1.5  cm.  or  about  half  an  inch  in  front  of  the  ear,  the  structures  to  be  avoided 
are  the  duct  and  facial  nerve.  The  incisions  are  to  be  made  parallel  to  the  zygoma, 
and  the  duct  is  to  be  avoided  by  not  cutting  on  a  line  joining  the  lower  edge  of  the 
cartilage  of  the  ear  with  the  middle  of  the  upper  lip.      The  branches  of  the  facial 

nerve  lie  deep  and  are  to  be  avoided  by 
making  the  incision  parallel  to  their  course,. 
and  not  extending  it  too  deeply.  After  in- 
cising the  skin,  the  deeper  tissues  may  be 
separated  by  introducing  a  pointed  pair  of 
haemostatic  forceps  and  opening  the  blades. 
In  o])erating  in  the  region  below  the  ear, 
the  blood-vessels  are  to  be  avoided.  To  do 
this  incise  the  skin  longitudinally,  not  trans- 
\'ersely,  and  open  the  deep  parts  carefully 
with  the  hfemostatic  forceps,  as  already 
described.  Another  method,  when  the  ab- 
scess is  farther  forward,  is  to  make  a  hori- 
zontal incision  rather  low  down  on  the  angle 
of  the  jaw  and  then  introduce  a  grooved 
director  or  hEemostatic  forceps  from  below 
upward. 

Tumors  of  the  parotid  gland  are  liable 
to  be  mixed  in  character,  with  a  sarcoma- 
tous element.  They  are  often  fairly  cir- 
cumscribed and,  particularly  if  they  do 
not  involve  the  parotid  duct,  can  be  re- 
mo\'ed  comparati\'ely  readily.  If  they  are 
malignant  and  large,  complete  removal  is 
practically  impossible.  The  possibilit}'  of 
parotid  fistula  and  paralysis  of  the  facial 
nerve  following  operation  on  this  gland  should  always  be  borne  in  mind  and  explained 
to  patients.  The  presence  of  facial  paralysis  is  indicative  of  malignancy  (see  Fig.  63). 
The  parotid  lymph  nodes  on  or  beneath  the  capsule  may  become  enlarged  and 
inflamed  and  resemble  true  parotiditis.  There  is  one  node  just  below  the  zygoma 
and  in  front  of  the  ear  that  is  not  infrequently  enlarged  in  strumous  children.  This 
is  apt  to  be  involved  when  affections  of  the  lids  or  scalp  are  present.  In  open- 
ing abscesses  of  these  nodes  there  is  little  likelihood  of  injuring  either  the  nerve  or 
the  duct,  because  the  nodes  are  superficial.  The  transverse  facial  artery  is  usually 
too  small  to  cause  trouble.  The  possibility  of  its  supplying  the  coronary  arteries 
of  the  lips,  as  already  described,  in  which  case  it  would  be  verj'  large,  should  be 
remembered. 

THE   UPPER   JAW. 

The  upper  jaw  carries  the  upper  teeth  and  contains  the  maxillar)-  sinus  or 
antrum  of  Highmore.  The  affections  of  the  antrum  will  be  alluded  to  in  the  chapter 
on  the  nose  (see  page  103).  Fractures  of  the  superior  maxilla  involve  the  nasal 
process,  the  ah'eolar  process,  or  pass  trans\-ersely  through  the  body  of  the  bone. 
The  nasal  process  is  sometimes  broken  in  fractures  of  the  nose.  In  this  injury,  the 
lachrymal  canal  and  sac  may  be  injured  and  the  flow  of  tears  through  them  pre- 
vented, causing  the  tears  to  run  over  the  cheek. 

Fractures  of  the  ah'eolar  process  are  common  enough  as  a  result  of  blows  and 
e.xtracting  teeth.  These  fractures,  as  they  communicate  with  the  mouth  through  the 
broken  gums  or  mucous  membrane  or  tooth  socket,  are  necessarily  compound,  and 


-Malignant  tumor  of  the  parotid  gland  pro- 
lucing  facial  paralysis  (author's  case). 


THE   FACE. 


55 


consequently  become  infected  from  the  mouth  and  suppurate.  This  may  cause 
necrosis  of  the  fragment,  but  the  blood  supply  of  the  jaws  is  so  good  that  death  of 
a  fragment  is  rare,  and  it  is  not  customary  to  remove  fragments  not  completely 
detached.      The  front  wall  is  sometimes  driven  in. 

Fractures  occasionally  occur  in  which  the  line  passes  through  one  or  both  supe- 
rior maxillary  bones  from  below  the  malar  bone  into  the  nose.  If  this  fracture  passes 
completely  backward,  it  detaches  the  lower  portion  of  the  palate  bone  and  pterygoid 
processes  of  the  sphenoid  bone.  The  fragment  in  such  cases  has  a  tendency  to  slip 
backward.  It  can  be  replaced  by  inserting  a  hook  through  the  mouth  and  behind 
the  soft  palate  and  pulling  the  fragment  forward.  This  injury  is  produced  by  a  blow 
on  the  anterior  portion  of  one  or  both  bones,  passing  downward  and  backward.  In 
order  to  determine  the  existence  of  fracture,  Guerin  recommended  inserting  the  finger 
in  the  mouth  and  feeling  for  the  pterygoid  plates.  The  hamular  process  of  the  internal 
pterygoid  plate  can  readily  be  felt  about 
one  centimetre  above  and  behind  the  last  ^  ^ 

upper  molar  tooth.  Fractures  in  the  neigh- 
borhood of  the  first  and  second  molar  teeth 
are  liable  to  open  the  antrum,  as  the  roots 
of  these  teeth  project  into  it. 

Resection  of  Upper  Jaw. — Tumors 
of  the  antrum  may  necessitate  a  resection 
of  the  superior  ma.xilla  of  one  side.  Hey- 
felder  was  the  first  to  remove  both  superior 
maxillse,  in  1844:  this  was  before  the  dis- 
covery of  anaesthesia.  In  removing  one 
superior  maxilla,  the  incision  known  as  Fer- 
gusson's  is  used.  This  is  made  through 
the  middle  of  the  upper  lip,  around  the  ala 
of  the  nose  to  the  inner  canthus  of  the  eye, 
thence  outward  along  the  lower  border  of 
the  orbit  to  the  malar  bone.  The  bleeding 
from  this  incision  is  free.  The  coronary 
arteries  should  be  looked  for  near  the 
mucous  surface  of  the  lip  toward  its  free 
edge.  Bleeding  will  also  occur  from  the 
lateralis  nasi  and  the  angular  arteries.  The 
soft  parts  are  raised  from  the  bones  as  far 
back  as  the  masseter  muscle.  This  is  just 
about  level  with  the  outer  edge  of  the  bony 

orbit.  In  doing  so  the  infra-orbital  nerve  and  artery  will  be  divided.  The  artery  is 
not  large  but  may  bleed  freely.  The  fibrous  floor  of  the  orbit  is  raised  and  the  attach- 
ment of  the  inferior  oblique  muscle  loosened.  The  malar  bone  is  sawed  downward 
and  outward  opposite  the  sphenomaxillary  fissure,  and  the  division  completed  with 
forceps.  The  nasal  portion  of  the  superior  maxilla  is  sawed  through  from  the  orbit 
into  the  nose.  The  soft  parts  of  the  roof  of  the  mouth  are  divided  in  the  median 
line  to  the  posterior  edge  of  the  hard  palate,  and  thence  along  its  edge  to  the  last 
molar  tooth.  The  soft  palate  is  firmly  attached  to  the  hard  palate  and  has  to  be 
detached  with  scissors.  An  incisor  tooth  is  then  drawn,  and  the  bony  palate  sawed 
through  from  the  nose  into  the  mouth.  The  bone  with  the  tumor  is  wrenched  loose 
with  lion-jawed  forceps.  The  union  between  the  posterior  portion  of  the  superior 
maxilla  and  the  pterygoid  processes  of  the  sphenoid  is  not  bony,  but  fibrous,  so  that 
the  bone  is  torn  awav  from  the  processes  and  the  latter  are  left  behind.  As  the  bone 
comes  awav,  the  maxillarv  ner^^e  should  be  cut.  The  bleeding  which  follows  is  from 
the  infra-orbital,  superior'alveolar  (posterior  dental),  and  posterior  palatine  arteries, 
branches  of  the  internal  maxillary.  It  is  not  so  free  as  might  be  expected,  provided 
preliminary  ligation  of  the  external  carotid  has  been  performed.  It  will  be  observed 
that  the  facial  nerve  is  not  touched  nor  is  the  parotid  duct  wounded. 

Neuralgia  of  the  Maxillary  Nerve. — The  pain  involves  the  cheek  from  the 
eye  to  the  mouth  and  as  far  forward  as  the  median  line,  also  the  upper  gums  and 


Fig.  64. — Resection  of  the  upper  jaw.  The  curved 
lines  indicate  the  skin  incision  and  the  straight  lines 
where  the  bones  are  to  be  divided. 


56  APPLIED    ANATOMY. 

hard  palate.  The  operations  devised  for  its  relief  are  both  numerous  and  intricate, 
and  necessitate  an  accurate  anatomical  knowledge  of  the  parts.  The  maxillary 
nerve  is  the  second  division  of  the  fifth  cranial  nerve.  It  leaves  the  skull  cavity  by 
the  foramen  rotundum,  then  crosses  the  sphenoma.xillary  fossa,  enters  the  spheno- 
ma.xillary  fissure  and  infra-orbital  canal  to  emerge  on  the  cheek,  opposite  the  middle 
of  the  lower  edge  of  the  orbit  and  about  6  mm.  below  it.  The  intracranial  portion 
is  6  to  8  mm.  in  length.  From  the  sphenomaxillary  fossa  to  the  infra-orbital  fora- 
men is  about  5  cm.  (2  in. ).  Its  branches  are  as  follows:  one  or  two  small  branches 
to  the  dura  mater,  the  orbital  or  sphenomalar  branch  to  the  cheek  and  anterior  tem- 
poral region,  sphenopalatine  branches  going  to  Meckel's  ganglion,  the  posterior, 
middle,  and  anterior  dental  to  the  upper  teeth,  and  the  terminal  branches,  labial, 
nasal,  and  palpebral,  on  the  face. 

Its  anterior  portion  has  been  removed  through  an  incision  on  the  face,  and  its 
posterior  portion  with  Meckel's  ganglion  has  been  operated  on  either  anteriorly 
through  the  maxillary  sinus  or  laterally  through  the  temporal  fossa,  after  removing 
the  zygoma.  The  writer  has  removed  the  intracranial  portion  by  entering  the  ante- 
rior cerebral  fossa  through  the  temporal  region.    Removal  of  the  infra-orbital  portion 


Infra-orbital  artery 


Fro.  65.— Exposure  of  the  infra-orbital  nerve  and  artery. 

of  the  nerve  is  so  liable  to  be  followed  by  recurrence  of  the  pain  and  interferes  so 
much  with  the  more  complete  procedures,  as  it  destroys  the  guide  (the  nerve  itself) 
which  leads  the  operator  to  Meckel's  ganglion,  that  it  is  doubtful  whether  it  should 
ever  be  resorted  to.  The  posterior  dental  branches  are  given  of!  so  far  back  that 
they  are  not  apt  to  be  removed  in  this  operation. 

Removal  of  the  Infra-orbital  Nerve. —  An  incision  3  cm.  in  length  is  made 
along  the  lower  edge  of  the  orbit.  This  divides  the  orbicularis  palpebrarum  muscle. 
Arising  from  the  bone,  between  the  infra-orbital  foramen  and  the  edge  of  the  orbit, 
is  the  levator  labii  superioris  muscle.  This  should  be  carefully  detached,  and  the 
foramen  with  its  artery  and  nerve  will  be  found  opposite  the  middle  of  the  lower  edge 
of  the  orbit  and  about  6  mm.  (y^  in. )  below  it,  on  a  line  drawn  from  the  supra-orbital 
notch  to  between  the  premolar  teeth.  The  position  of  the  foramen  having  been 
located,  the  palpebral  ligament  and  periosteum  are  divided  and  the  contents  of  the 
orbit  raised.  The  canal  is  ne.xt  to  be  opened.  This  can  be  done  either  by  chiselling 
away  its  roof  from  the  opening  on  the  face  and  following  it  backward  or  by  breaking 


THE   FACE. 


57 


through  its  upper  wall.  This  latter  procedure  is  liable  to  give  trouble,  because  if 
the  track  of  the  canal  is  not  encountered  the  instrument  breaks  into  the  maxillary- 
sinus,  the  roof  of  which  is  very  thin.  The  infra-orbital  canal  does  not  pass  direcdy 
backward  but  backward  and  outward,  striking  the  sphenomaxillary  fissure  about  2 
cm.  (in  a  large  skull)  behind  its  anterior  extremity.  Sometimes  the  roof  of  the 
canal  is  fibrous,  in  which  case  the  groove  so  formed  can  be  readily  felt,  but  in  others 
it  is  bony.  The  nerve  is  hooked  up  and  cut  as  far  back  as  one  can,  so  as  to  remove, 
if  possible,  the  posterior  dental  branches.  The  terminal  branches  are  then  pulled  off 
from  the  cheek,  and  the  nerve  drawn  out  from  the  front.  It  is  in  the  highest  degree 
desirable  to  avoid  wounding  the  artery,  as  death  is   said  to  have  followed  it,  and 


•^  iniffMW^'°- 


Ophtha 

Iniic  branch- 

-Sih  nerve 

Motor 

root 

1         Sensory  root 

/ 

Ma. 

lary  branch 

1/. 

asser,an  ganglion 

^ 
^.'<^ 

^,_^-^\^^^^ 

-'Middle  niening^eal  artery 
^  Mandibular  branch 
^^Temporomalar  nt^rve 

^^-^  Buccal  branch 

^ter""^*^^-^ 

\            Stump  of  external 
-i--'"'^    pterygoid  muscle 

^^^-- Lingual  nerve 
__  Inferior  alveolar 

Infra-orbital 
nerve  and  arterj  ' 


^ZA 


Fig.  66.— The  fifth  or  trifacial  nerve  with  its  various  branches. 

there  may  be  bleeding  into  the  orbit,  causing  protrusion  of  the  eye  and  serious  inter- 
ference with  its  sight.  A  better  way  of  removing  the  nerve,  the  method  of  Thiersch 
(  Verhand.  der  Deiitschen  Gesell.  fiir  Chir.,  18  Congress,  Berlin,  1S89,  p.  44J,  is  to 
grasp  it  with  a  pair  of  slender,  curved  forceps,  then  by  rotating  the  forceps  very 
slowly  (about  i  turn  a  minute)  both  the  distal  and  proximal  ends  are  wound  around 
it  and  an  extremely  long  portion  of  the  nerve  can  be  removed. 

Removal  of  Meckel's  Ganglion.  —  Operating  from  the  front  through 
the  maxillary  sinics  (Carnochan's  operation,  or  removal  of  the  sphenopalatine 
(Meckel's)  ganglion  and  maxillary  nerve). — The  incision  is  V-shaped,  the  apex 
being  2  cm.  above  the  angle  of  the  mouth,  and  the  branches  3  cm.  long.  This  flap 
should  consist  of  all  tissues  down  to  the  bone.  The  bleeding  will  be  free,  as  the 
facial  vein  and  branches  of  the  facial  artery  will  be  cut.  As  the  infra-orbital  foramen 
is  reached,  the  nerve  is  detached  from  its  under  surface.      The  anterior  wall  of  the 


58  APPLIED    ANATOMY. 

maxillary  sinus,  which  is  quite  thin,  is  broken  with  a  chisel  for  an  extent  of  2  cm. 
The  infra-orbital  canal  is  opened  from  below,  from  the  surface  clear  back  to  the  pos- 
terior wall  of  the  sinus.  The  infra-orbital  nerve  is  then  brought  down  into  the  sinus 
to  serve  as  a  guide  to  the  foramen  rotundum.  Care  should  be  taken  (by  opening 
the  canal  with  comparatively  blunt  instruments)  not  to  wound  the  infra-orbital  artery. 
Then  break  a  hole  in  the  posterior  wall  of  the  sinus.  This  is  very  thin,  and  not  over 
half  a  centimetre  (i  in. )  intervenes  between  it  and  the  anterior  wall  of  the  sphenoidal 
sinus,  so  that  care  should  be  taken  not  to  dri\'e  the  chisel  too  far  back.  The  pos- 
terior wall  having  been  broken  with  the  chisel  and  the  pieces  picked  away,  the  nerve 
is  dragged  downward,  freed  as  far  back  as  possible,  and  pulled  loose.  Traction  on 
the  nerve  brings  the  ganglion  forward,  and  with  forceps  it  is  then  drawn  out.  The 
bleeding,  after  breaking  through  the  posterior  wall  of  the  sinus,  may  be  very  free. 
Meckel's  ganglion  lies  in  the  sphenopalatine  fossa  just  below  the  maxillary  nerve 
after  it  leaves  the  foramen  rotundum.  Two  short  branches  unite  the  ganglion  and 
nerve.  It  is  here  that  the  internal  maxillary  artery,  in  the  third  part  of  its  course, 
divides  into  six  branches:  the  itifra-orbital  and  posterior  dental,  the  posterior  or 
desce?idifig  palatine  and  Vidian,  and  the  pterygopalatine  and  spheno-  or  nasopalatine 
arteries.  If  these  arteries  are  wounded,  as  they  are  very  apt  to  be,  the  bleeding  is 
very  free.  To  control  it  temporary  packing  is  at  first  resorted  to.  If  it  persists,  the 
nerve  is  removed  as  well  as  possible  and  the  bleeding  stopped  with  gauze.  This 
may  be  firmly  packed  into  the  opening  through  the  posterior  wall  at  the  upper  inner 
portion  of  the  sinus,  but  care  should  be  taken  not  to  push  it  roughly  through  the 
fossa  and  into  the  sphenoidal  sinus  (or  cells)  beyond. 

J.  D.  Bryant  (  Operative  Siu-gery,  vol.  i,  p.  243)  in  cases  of  severe  hemorrhage 
advises  the  prompt  ligation  of  the  external  carotid  artery,  a  procedure  not,  however, 
often  required.  It  has  been  suggested  that  instead  of  making  the  incision  on  the 
cheek  to  make  it  in  the  mouth  above  the  gums,  and  pull  the  cheek  and  mouth 
upward  and  outward.  This  procedure,  while  obviating  the  scar,  makes  the  opera- 
tion  somewhat  more  difficult.  Kocher  resects  the  malar  bone  with  the  outer  wall  of 
the  sinus  and  turns  it  up,  bringing  it  back  into  place  on  the  completion  of  the 
operation. 

Operating  from  the  Side  Through  the  Pterygoid  Fossa. — Both  the 
maxillary  and  mandibular  branches  have  been  reached  by  this  route;  the  former  at 
the  foramen  rotundum  and  the  latter  at  the  foramen  ovale.  Liicke,  of  Strasburg, 
Vv'as  the  pioneer  of  the  operation  on  the  maxillary  nerve,  and  Joseph  Pancoast,  of 
Philadelphia,  on  the  mandibular.  Liicke' s  operation  was  modified  by  Lessen,  of 
Heidelberg.  Recently,  Mixter,  of  Boston,  has  again  advocated  the  method.  A 
convex  flap,  base  down  and  reaching  3 2  inch  below  the  zygoma,  is  cut  from  the 
external  margin  of  the  orbit  to  the  lobe  of  the  ear.  The  zygoma  is  sawed  through, 
and,  with  the  masseter,  pulled  downward.  Maurice  Richardson,  in  describing  Mix- 
ter's  operation  {Internat.  Textbook  of  Sn7-g.,  vol.  i,  p.  863),  saj'S  that  "if  the 
operator  is  skilled  enough  in  the  subsequent  manipulations,  he  may  omit  cutting  the 
temporal  muscle."  It  will  be  easier,  however,  to  divide  the  coronoid  process  and 
turn  the  temporal  muscle  upward,  clearly  exposing  the  infratemporal  crest.  Detach 
the  upper  head  of  the  e.xternal  pterygoid  muscle  and  push  it  downward,  exposing 
the  external  pterygoid  plate.  Chisel  off  the  spur  at  the  anterior  extremity  of 
the  infratemporal  crest,  and  immediately  in  front  and  to  the  inner  side  is  the  supe- 
rior maxillary  nerve,  with  the  terminal  portion  of  the  internal  ma.xillary  artery 
just  below  it.  Immediately  posterior  to  the  root  of  the  pterygoid  plate  is  the 
foramen  ovale  and  mandibular  nerve,  with  the  middle  meningeal  artery  a  little 
posterior  to  it. 

Anatomical  Comments. — The  incision  at  its  posterior  extremity  can  be 
made  to  avoid  cutting  the  temporal  artery  by  feeling  its  pulsations,  about  a  centimetre 
or  less  in  front  of  the  ear,  as  it  passes  over  the  zygoma.  The  incision  should  not 
involve  the  deep  structures — only  the  skin  and  superficial  fascia.  Therefore,  the 
facial  nerve  and  parotid  duct  (a  finger's  breadth  below  the  zygoma)  will  not  be 
injured. 

In  clearing  the  upper  surface  of  the  zygoma,  it  will  be  necessary  to  cut  through 
the  layers  of  the  temporal  fascia;    between  them  the  orbital  branch  of  the  temporal 


THE  FACE. 


59 


artery  may  be  encountered  and  may  bleed.  The  temporal  muscle  arises  not  only 
from  the  deep  layer  of  the  temporal  fascia,  but  may  also  be  attached  anteriorly  to 
the  inner  surface  of  the  zygoma,  and  in  loosening  it  free  bleeding  from  the  deep 
temporal  arteries,  branches  of  the  internal  ma.xillary,  may  be  encountered.  No 
trouble  need  be  expected  in  sawing  through  the  anterior  end  of  the  zygoma,  but  care 
should  be  taken  not  to  injure  the  parotid  duct,  or  the  socia  parotidis  if  it  is  present. 
In  making  the  division  of  the  posterior  end  of  the  zygoma,  one  must  guard  against 
opening  the  temporomaxillary  articulation,  for,  when  the  head  of  the  mandible  is 
back  in  the  glenoid  fossa,  the  capsule  of  the  joint  extends  considerably  in  front  of  it 
Therefore,  it  is  better  to  open  the  mouth  and  push  the  jaw  on  that  side  forward  until 
it  rides  on  the  eminentia  articularis,  then  the  anterior  limit  of  the  joint  can  be  recog- 
nized and  avoided.  Before  one  can  reach  the  spur  on  the  anterior  extremity  of  the 
infratemporal  crest,  the  temporal   muscle  must  be  detached  from  the  bone.      The 


Processus  coronoideus 


Crista  iiifratempo- 
Spur 

ixillaris 


A    infra-orbitalis 
A.  temporalis 
proluiidus 
A.  alveolaris 
posterior 
A.  maxiUaris 
interims 


M.  ptery 

ternus.     Upper  head 
turned  down 


Fig.  67.— Operating  through  the  pterygoid  fossa.  The  skin  with  the  zygoma  and  masseter  have  been  turned 
down.  The  coronoid  process  is  divided  and  turned  up.  The  upper  head  of  the  external  pterygoid  has  been 
detached  and  turned  down.  The  maxillary  nerve  is  in  front  of  the  pterygoid  plate  (processus  pterygoideus)  and 
the  mandibular  nerve  and  middle  meningeal  artery  just  behind  it. 

Upper  head  of  the  external  pterygoid  muscle  arises  from  the  bone  just  below  the 
pterygoid  ridge  (infratemporal  crest),  and  must  be  loosened  from  the  bone  to  obtain 
access  to  the  nerves  (see  Fig.  67). 

The  coronoid  process  rises  almost  as  high  as  the  infratemporal  crest,  and,  there- 
fore, in  order  to  gain  space  it  will  be  necessary  to  depress  the  jaw.  Running  upward 
and  inward  over  the  internal  pterygoid  muscle,  and  passing  just  in  front  of  the  origin 
of  the  upper  head  of  the  external,  is  the  internal  maxillary  artery  and  pterygoid 
plexus  of  veins.  These  vessels  lie  directly  below  the  maxillary  nerve  as  it  crosses 
the  sphenopalatine  fossa,  and  it  is  to  be  expected  that  free  hemorrhage  will  accom- 
pany the  attempt  to  fish  out  the  nerve. 

In  operating  in  this  region,  one  surgeon  found  the  bleeding  so  severe  as  to 
require  the  ligation  of  the  e-xternal  carotid  artery. 

Intracranial  operations  are  hardly  ever  done  for  maxillary  neuralgia  alone.  The 
mandibular  and  often  the  ophthalmic  divisions  are  also  usually  affected  in  cases 
requiring  to  be  approached  from  the  inside  of  the  skull. 


6o 


APPLIED    ANATO.MY. 


Excision  of  the  Lingual  and  Inferior  Dental  Nerves. — Neuralgia  in- 
volving the  face  below  the  line  of  the  mouth,  the  lower  teeth,  and  side  of  the  tongue 
requires  the  removal  of  the  inferior  dental  and  lingual  nerves.  To  do  this,  a  curved 
incision  following  the  lower  edge  of  the  mandible  is  made.  It  ends  anteriorly  in 
front  of  the  mandibular  foramen,  and  posteriorh^  it  stops  a  centimetre  below  the  ear  to 
avoid  wounding  the  facial  nen^e.  The  masseter  muscle  is  raised  from  the  bone,  and, 
with  the  parotid  gland,  is  drawn  up.  The  ramus  of  the  jaw  is  trephined  in  its  middle, 
rather  high  up  toward  the  coronoid  notch.  The  outer  table  of  bone  is  then  to  be 
chiselled  off,  from  the  trephine  opening  as  far  down  as  the  mental  foramen.  A 
delicate,  cun^ed,  hsemostatic  forceps  is  then  made  to  grasp  both  ner\'es  through  the 


Internal  pterygoid 
Mandibu 


Fig.  6S.— Excis 


ndibular  (inferior  dental)  i 


trephine  opening,  and  on  rotating  very  slowly  the  nerves  are  wound  around  the  for- 
ceps and  are  gradually  torn  loose  from  the  base  of  the  skull  above  to  their  ultimate 
branches  below  (see  Fig.  68). 

Operations  on  the  Gasserian  Ganglion. — The  Gasserian  ganglion  lies  in 
its  capsule,  formed  by  a  splitting  of  the  dura,  on  the  anterior  surface  of  the  apex  of 
the  petrous  portion  of  the  temporal  bone  and  on  the  root  of  the  greater  wing  of  the 
sphenoid.  From  its  posterior  extremity,  which  rests  on  the  ridge  separating  the 
anterior  and  posterior  surfaces  of  the  petrous  portion  of  the  temporal  bone,  to  the 
foramen  rotundum  anteriorly  is  2. 5  to  3  cm.  (1  to  i}(  in.).  The  foramen  ovale,  Avhich 
transmits  the  third  or  mandibular  branch  is  midway  between  these  two  points,  and 
corresponds  on  the  outside  of  the  skull  to  the  eminentia  articularis  or  root  of  the 
zygoma.  Therefore,  in  removing  the  ganglion  one  works  not  only  inward  but  also 
backward.  Rose  first  operated  on  the  ganglion  from  below.  He  removed  the 
zygoma  and  coronoid  process,  ligated  the  internal  maxillar_v  artery,  and  trephined 
the  skull  in  front  of  the  foramen  ovale.  This  operation  was  succeeded  by  that  of 
Hartley  and  Krause.  They  went  in  through  the  temporal  fossa.  A  large  horseshoe- 
shaped  flap,  with  its  base  abo\'e  the  zygoma,  was  cut  and  deepened  with  chisels 
through  the  bone  to  the  dura.  This  was  elevated  by  breaking  across  its  base,  and  turn- 
ing it  down.  The  dura  was  then  lifted  from  the  base  of  the  skull,  and  the  maxillary 
and  mandibular  nerves  recognized  as  they  passed  into  the  round  and  oval  foramina. 
The  capsule  having  been  incised,  these  were  seized  with  forceps,  and  as  much  of  the 
ganglion  as  possible  torn  away. 

Other  surgeons,  like  Doyen,  Ouenu,  Poirier,  and  Gushing,  have  combined  these 
pterygoid  and  temporal  routes.      The  bone  flap,  as  made  by  Hardey  and  Krause, 


THE    FACE. 


6i 


embraced  the  region  of  the  pterion  or  junction  of  the  coronal  with  the  temporo- 
sphenoidal  sutures.  As  the  bone  was  lifted  from  the  dura  at  this  point  the  middle 
meningeal  artery  was  torn  and  troublesome  bleeding  ensued.  Also  the  point  of  its 
breaking  was  too  uncertain.  Sometimes  it  broke  too  high  up,  sometimes  too  low 
down  involving  the  base.  It  was  also  found  unnecessary  to  replace  the  bone  as 
the  cavity  left  was  filled  up  with  fibrous  tissue.  For  this  reason  Tiffany,  of  Baltimore, 
advocated  the  making  of  an  opening  in  the  skull  above  the  zygoma  with  a  trephine 
or  gouge  and  mallet,  and  enlarging  it  with  the  rongeur  forceps;  the  bone  was  not 
replaced.      This  is  the  procedure  now  used. 

The  operators  who  used  the  pterygoid  route,  by  displacing  the  zygoma  down- 
ward, were  enabled  to  approach  the  ganglion  from  below  instead  of  from  above, 
therefore,  a  high  temporal  section  of  the  bone  was  unnecessary  and  it  has  been 
abandoned;   the  bone  section   keeping  below  the   pterion   and    not  wounding   the 


J\I.  ptery_ 
extern  us,  upper  head 

M.  pteryi 
exteriius,low 

M.  pterygoideus 

N.  alveolaris  inferior 
(inferior  dental) 


Fig.  69. — The  upper  porti( 


1  of  the  illustration  shows  the  operation  of  removal  of  the  Gasserii 
emilunare).     The  lower  portion  shows  the  pterygoid  muscles. 


middle  meningeal  artery  thus  avoids  hemorrhage  from  that  locality.  Gushing 
{Journ.  Am.  Med.  Assoc,  April  28,  1900)  showed  that  the  extensive  removal  of  bone 
on  the  base  of  the  skull  was  unnecessary,  and  that  a  displacement  of  the  zygoma 
and  temporal  muscle  downward,  and  removal  of  the  bone  down  to  and  including 
part  of  the  infratemporal  crest  gave  sufhcient  access.  Murphy  found  it  unnecessary 
to  resect  the  zygoma,  and  this  has  been  our  experience. 

One  of  the  main  difficulties  has  been  the  question  of  bleeding.  It  has  caused 
death  and  not  infrequently  has  necessitated  the  packing  of  the  wound  and  the 
deferring  of  the  completion  of  the  operation  for  two  or  more  days.  This  bleeding 
came  from  the  soft  parts,  the  bone,  the  middle  meningeal  artery,  the  veins  running 
from  the  dura  mater  to  the  bone,  the  cavernous  sinus,  and  the  blood-\-essels  to  the 
ganglion  itself.  These  as  given  by  Gushing  are  a  branch  from  the  middle  meningeal 
soon  after  its  entrance  to  the  skull,  a  small  branch  from  the  carotid,  a  small  branch 
from  the  ophthalmic,  the  small  meningeal  through  the  foramen  ovale,  and  occasion- 
ally one  through  the  foramen  rotundum.  He  calls  attention  to  the  septa  in  the 
cavernous  sinus  as  rendering  wounds  to  it  less  serious  than  they  otherwise  would  be. 
If  the  skin  incision  is  cast  too  far  back,  the  temporal  artery  may  be  cut  in  front  of  the 
ear.  Its  position  can  be  determined  by  its  pulsation.  It  or  its  branches  are  divided 
in  the  upper  portion  of  the  incision  and  bleeding  is  very  free.  Division  of  the 
temporal  muscle  is  followed  by  hemorrhage  from  the  deep  temiporal.  The  bleeding 
from  the  bone  is  usually  not  troublesome,  but  the  general  oozing  from  the  veins  of 


62 


APPLIED    ANATOMY. 


the  dura  mater  as  it  is  detached  from  the  bone  is  sometimes  free.  If  an  osteoplastic 
(bone  and  skinj  flap  is  raised,  the  middle  meningeal  will  be  torn  at  the  pterion. 
This  is  a  large  vessel  and  bleeds  freely.  It  may  also  be  torn,  while  isolating  the 
mandibular  division  of  the  nerve,  at  the  foramen  spinosum.  This  foramen  is  usually 
a  couple  of  millimetres  posterior  and  to  the  outer  side  of  the  foramen  ovale  and 
generally  the  nerve  can  be  isolated  without  injuring  the  artery.  In  some  cases,  how- 
ever, the  artery  lies  so  close  to  the  nerve  that  it  is  almost  certain  to  be  torn.  The 
■posterior  portion  of  the  ganglion  hes  on  the  carotid  artery  in  the  middle  lacerated 
foramen,  of  course  separated  by  a  layer  of  dura  mater.  Care  should,  therefore,  be 
taken  not  to  injure  the  carotid  artery.  The  cavernous  sinus  has  often  been  injured. 
This  occurs  principally  in  those  cases  in  which  it  is  attempted  to  excise  the 
ophthalmic  division.  It  is  to  be  avoided  by  working  from  behind  forward  instead  of 
attempting  to  attack  it  laterally.      Bleeding  from  the  middle  meningeal  artery  can  be 


Maxillary' 


^distribution  of  cutaneous  branches  of  tr\^' 


avoided  by  biting  the  skull  away  with  the  rongeur  forceps  and  refraining  from 
detaching  the  dura  from  the  bone  where  the  artery  enters  it  (see  Fig.  23). 

Gushing  states  that  he  makes  an  opening  in  the  bone  only  3  cm.  in  diameter. 
Such  a  small  opening  is  used  when  the  zygoma  has  been  divided  and  pushed  down 
or  removed.  Fowler  and  others  have  resorted  to  a  preliminary  ligation  of  the 
external  carotid  artery.  This,  while  obviating  to  a  great  e.xtent  troublesome  hem- 
orrhage, cuts  off  the  blood  supply  to  the  flap  and  sloughing  has  followed.  In 
order  to  overcome  this  objection,  the  writer  (/o?irn.  Am.  Med.  Assoc,  April  28, 
1900)  after  ligating  the  external  carotid  artery  above  its  posterior  auricular  branch 
made  a  temporal  skin  flap  with  its  base  up.  The  temporal  muscle  was  then  divided 
and  turned  down  and  the  bone  removed  with  the  trephine  and  rongeur.  Haemostasis 
was  perfect  and  no  ill  effects  followed  the  ligation. 

It  is  comparatively  easy  to  isolate  the  maxillary  and  mandibular  divisions  of  the 
nerve.  This  having  been  done,  the  capsule  of  the  ganglion  is  opened  by  a  cut 
joining  the  two.  A  blunt  dissector  is  then  introduced  and  the  upper  layer  of  the 
dura,  less  adherent  than  the  lower,  is  raised  from  the  ganglion.  The  blunt  dissector 
is  then  worked  beneath  the  ganglion  beginning  between  the  maxillary  and  mandib- 
ular divisions  and  it  is  loosened  from  behind  forwards.  The  sixth  nerve  is  in  such 
close  relation  to  the  ophthalmic  that  a  temporary  paralysis  of  it  usually  follows, 
causing  internal  squint.  Anjesthesia  of  the  whole  side  of  the  face  from  just  in  front 
of  the  ear  to  the  median  line  follows  complete  removal.  Frazier  and  Spiller  have 
divided  the  root  posterior  to  the  ganglion  instead  of  removing  the  ganglion  itself 
{^Journ.  Am.  Med.  Assoc.,  Oct.  i,  1904,  p.  943). 


THE    FACE. 


63 


Area  of  Distribution  of  the  Fifth  Nerve. — When  the  ophthalmic  division 
is  affected  the  pain  in  neuralgia  is  over  the  brow  and  up  toward  the  vertex  of  the 
skull;  it  also  involves  the  eye.  The  points  of  exit  of  the  supra-orbital  branch  at 
the  supra-orbital  foramen  and  of  the  nasal  branch  toward  the  lower  portion  of  the 
nose  are  tender  to  pressure. 

When  the  maxillary  division  is  affected,  there  is  pain  in  the  cheek  and  ala  of 
the  nose.  The  tender  points  are  the  exit  of  the  infra-orbital  nerve  at  and  below 
the  infra-orbital  foramen,  at  the  exit  of  the  malar  branch  on  the  malar  bone,  and 
the  upper  gums  and  hard  palate. 

When  the  mandibular  division  is  affected  the  pain  involves  the  lower  jaw  and 
the  side  of  the  head  nearly  to  the  top  (auriculotemporal  branch).  The  lower  gums 
and  tongue  are  also  painful.  Pain  on  pressure  is  felt  over  the  mental  foramen  and  in 
the  course  of  the  auriculotemporal  nerve  in  front  of  and  above  the  ear. 


THE    LOWER   JAW. 
The  mandible  or  infei'ior  maxilla  is  subject  to  fractures,  dislocation,  and  tumors. 
In  its  composition  it  is  very  dense,  so  that  in  dividing  it  a  groove  should  be  cut 
with  a  saw  before    the    use    of   the   bone-cutting   forceps    is    attempted,   otherwise 


jaw  of  child  and  adult,  sh 


the  mental  foramen. 


splintering  of  the  bone  will  ensue.  It  is  the  last  bone  to  decay.  Its  horseshoe 
shape  and  exposed  position  render  it  unusually  liable  to  fracture.  The  strongest 
portion  is  what  one  would  expect  to  be  the  weakest,  viz. ,  the  symphysis.  Its 
weakest  part  (or  rather  the  part  where  it  is  most  often  broken)  is  the  region  of  the 
mental  foramen.  The  bone  is  weakened  at  this  point  not  only  by  the  foramen 
but  also  by  the  deep  socket  of  the  canine  tooth. 

The  position  of  the  mental  foramen,  normally  between  the  two  bicuspids 
(beneath  the  second  in  the  negro — Humphry),  varies  in  its  vertical  location  between 
the  alveolar  border  and  lower  edge  of  the  body,  according  to  age.  In  infancy  it  is 
low  down,  in  young  adults  it  is  midway,  and  in  old  people  it  is  high  up. 

The  body  of  the  jaw  is  composed  of  two  parts,  one  above  and  one  below  the 
external  oblique  line,  which  runs  from  the  base  of  the  anterior  border  of  the 
coronoid  process  downward  and  forward  to  end  at  the  mental  tubercle,  to  one  side 
of  the  symphysis.  The  part  above  this  oblique  line  is  the  alveolar  and  the  part 
below  is  the  basal  portion  of  the  body. 

The  mental  foramen  opens  on  the  oblique  line  separating  the  alveolar  and  basal 
portions.  In  early  adult  life  the  two  portions,  basal  and  alveolar,  are  about  even  in 
size,  so  that  the  foramen  is  below  the  middle  of  the  jaw.  As  the  teeth  are  lost 
the  alveolar  process  atrophies ;  this  naturally  leaves  the  basal  portion  with  the  mental 


64 


APPLIED    ANATOMY, 


foramen  on  or  near  its  upper  surface;  therefore,  in  operating  for  neuralgia  in  the 
aged,  if  it  is  desired  to  attack  the  mandibular  nerve  in  its  canal,  it  should  be  searched 
for  n-ear  the  upper  border  of  the  bone. 

In  infancy  the  teeth,  not  having  erupted,  are  contained  in  the  jaw,  the  alveolar 
portion  is,  therefore,  large.  The  basal  portion,  on  the  contrary,  is  quite  small,  serv- 
ing merely  as  a  narrow  shelf  on  which  the  unerupted  teeth  lie.  As  the  mandibular 
ner\-e  runs  beneath  the  teeth,  the  mental  foramen  is  of  necessity  comparati\-ely  low. 
At  birth  the  condyle  is  about  le\"el  with  the  upper  portion  of  the  symphvsis,  and  the 
bod}'  forms  with  the  ramus  an  angle  of  175  degrees.  At  the  end  of  the  fourth  year 
the  angle  has  decreased  to  about  140  degrees.  By  adult  age  the  angle  has  decreased 
to  about  115  degrees,  and  as  the  teeth  are  lost  the  angle  gradually  increases  until  it 
again  reaches  140  degrees. 

Temporomandibular  Articulation. — A  knowledge  of  the  movements  of  the 
jaw  is  essential  to  a  proper  understanding  of  the  fractures  and  dislocations  to  which 
it  is  subject. 


Temporalis 


Discus  articularis 


Processus  condvloideus 


Pterygcideus  externu 


Fig.  72. — The  temporomandibular  articulation. 

The  mandible  articulates  ^^•ith  the  glenoid  fossa  and  its  anterior  edge  or  emi- 
nentia  articularis  of  the  temporal  bone.  Interposed  between  the  condyle  below  and 
the  bone  above,  is  an  interarticular  cartilage.  This  divides  the  articulation  into 
two  portions,  an  upper  and  a  lower.  The  ligaments 
are  a  capsular,  strengthened  b}'  an  external  lateral 
(temporomandibular)  and  an  internal  lateral.  The 
capsular  ligament  is  weakest  anteriorly  and  strongest 
on  the  outer  side.  The  thickening  of  the  capsule 
on  its  outer  side  forms  the  external  lateral  or  tem- 
poromandibular ligament.  The  sphenomandibular 
or  internal  lateral  ligament  is  practically  distinct 
from  the  articulation.  It  runs  from  the  alar  spine 
on  the  sphenoid  above  to  the  mandibular  spine  or 
lingula,  just  posterior  to  the  mandibular  foramen 
below.  Between  it  and  the  neck  of  the  bone  ran 
the  internal  maxillary  artery  and  vein.  When  the 
condyle  glides  forward  it  puts  the  posterior  portion 
of  the  capsule  on  the  stretch,  and  if  the  jaw  is  dislocated  this  part  of  the  capsule  is 
torn.  The  interarticular  cartilage  is  more  intimately  connected  with  the  lower  por- 
tion of  the  articulation.  The  same  muscle  that  inserts  into  the  neck  of  the  jaw  (the 
external  pterygoid)  likewise  inserts  into  the  cartilage ;  therefore,  the  two  move 
together,  so  that  when  the  condyle  goes  forward  the  cartilage  goes  forward  and  rides 
on  the  eminentia  articularis. 


Fig.  73. — E.vterual  lateral  ligament  of  the 
lower  jaw. 


THE    FACE. 


6S 


Movements  of  the  Jaw. — The  jaw  has  four  distinct  movements.  It  can  be 
moved  directly  forward  or  backward;  up  and  down,  a  pure  hinge  motion;  a  rotary 
movement  on  a  vertical  axis  through  one  of  the  condyles;  and  rotation  on  a  trans- 
verse axis  passing  from  side  to  side 
through  the  mandibular  or  inferior 
dental  foramina.  The  muscles  of  mas- 
tication are  the  temporal,  niasseter, 
and  pterygoids ;  these  are  supplied  by 
the  motor  branch  of  the  fifth  nerve. 
To  these  we  may  add  the  buccinator, 
which  is  supplied  by  the  seventh  nerve, 
and  the  depressors  of  the  jaw, — the 
digastric,  geniohyoid,  geniohyoglos- 
sns,  mylohyoid,  and  platysnia.  The 
posterior  belly  of  the  digastric  receives 
its  nerve  supply  from  the  facial ;  its 
anterior  belly  from  the  mylohyoid 
branch  of  the  inferior  dental  from  the 
fifth.  The  mylohyoid  is  supplied  by 
the  mylohyoid  branch  of  the  inferior 
dental.  The  geniohyoid  and  genio- 
hyoglossus  are  supplied  by  the  hypo- 
glossal nerve.  The  platysma  is  sup- 
plied by  the  inframandibular  branch 
of  the  facial  nerve.  The  upward  move- 
ment is  produced  mainly  by  the  mas- 
seter  and  temporal  muscles.  It  is  the 
principal  movement  in  carnivorous 
animals  ;  therefore,  these  muscles  in 
them  are  well  developed,  and  the  joint  is  a  pure  hinge  joint.  The  internal  pterygoid 
and  buccinator  likewise  aid  in  closing  the  mouth  ;  the  depressors  already  mentioned 
open  it.      The  lateral  or  rotary  movement  around  a  vertical  axis  passing  through  one 

condyle  is  used  in  chewing  ;  therefore,  we 
find  the  muscles  most  concerned,  the  ptery- 
goids, best  developed  in  herbivorous  ani- 
mals, or  those  which  chew  the  cud.  The 
external  pterygoid  is  especially  efficient  in 
pulling  the  jaw  forward  ;  superficial  fibres 
of  the  masseter  help  in  this.  The  posterior 
fibres  of  the  temporal  muscle  pull  the  jaw 
back,  as  do  likewise  the  depressor  muscles 
of  the  jaw.  In  this  rotary  movement  one 
condyle  remains  back  in  its  socket  while  the 
other  is  brought  forward  on  the  eminentia 
articularis. 

The  up-and-down  movement  of  the 
jaws,  when  limited  in  extent,  is  a  pure  hinge 
movement  without  any  anteroposterior  dis- 
placement, and  takes  place  between  the  con- 
dyle and  the  interarticular  cartilage  (Fig.  . 
74).  The  anteroposterior  movement  is 
necessarily  accompanied  by  a  slight  descent 
of  the  jaw,  as  the  condyle  glides  from 
the  glenoid  ca^•ity  (Fig.  75)  onto  the  emi- 
nentia articularis.  It  goes  nearly,  but  not 
quite,  to  the  highest  point  of  the  articular 
eminence.  If  the  jaws  are  kept  closed  during  this  anteroposterior  movement,  some 
of  the  teeth  of  the  upper  and  lower  jaws  will  still  be  in  contact,  the  number  varying 
in  different  individuals      '^'      ■  ■  •  

5 


Fig.  75.— Illustrating  direct  anteroposterior 
ment  of  the  mandible.  The  condyle  is  resting 
eminentia  articularis. 


The  last  molar  teeth  are  usually  higher  than  those  in  front, 


66  APPLIED    ANATOMY. 

so  that  as  they  ghde  forward  the  last  lower  molars  strike  the  second  upper  ones. 
The  incisors  likewise  can  be  kept  in  contact  as  the  jaw  moves  backward  and  forward. 
It  is  this  movement  in  the  rodent  animals  which  keeps  their  edges  sharp.  In  chew- 
ing, the  jaw  is  depressed,  the  teeth  separated,  and  the  food  held  between  them  by  the 
tongue  and  buccinator  muscle.  The  teeth  are  then  approximated  by  the  lower  jaw 
closing  and  the  condyle  sliding  upward  and  backward  from  the  eminentia  articularis 
into  the  glenoid  cavity,  carrying  with  it  the  articular  cartilage. 

The  hinge  motion  takes  place  between  the  condyle  and  the  interarticular  carti- 
lage. The  anteroposterior  motion  takes  place  between  the  interarticular  cartilage  and 
the  eminentia  articularis:  the  cartilage  is  carried  forward  with  the  mandible.  A  rotary 
movement  occurs  when,  in  chewing,  the  condyle  of  one  side  remains  in  the  glenoid 
cavity  while  that  of  the  other  rises  on  the  articular  eminence.  The  radius  of  rotation 
is  a  line  passing  from  one  condyle  to  the  other.  In  widely  opening  the  mouth,  as 
in  yawning,  the  condyles  are  tilted  forward  while  the  angles  of  the  mandible  are 


Temporal  muscle 


External  lateral  ligament 


Internal  pterygoid  muscle 


Masseter  muscle 


Fig.  76. — Dislocation  of  the  lower  jaw ;  the  zygitma  and  part  of  the  masseter  muscle  have  been  cut  away. 

carried  somewhat  backward.  As  the  a.xis  of  this  motion  passes  from  side  to  side 
through  the  mandibular  foramina,  this  portion  of  the  bone  moves  but  little,  and  the 
inferior  dental  vessels  and  nerve  are  not  put  on  the  stretch. 

Dislocation  of  the  Lower  Jaw. — The  forward  dislocation  is  practically  the 
only  one  to  which  the  jaw  is  subject.  Dislocations  in  other  directions  are  apt  to  be 
accompanied  by  fractures.  An  understanding  of  the  mechanism  of  the  production 
and  reduction  of  this  dislocation  requires  a  knowledge  of  the  movements  of  the  jaw, 
and  the  influences  which  the  ligaments  and  muscles  exert  in  limiting  them.  The 
normal  movements  of  the  jaw  have  already  been  discussed. 

The  ligaments  which  hmit  the  movements  of  the  jaw  are  those  forming  the  cap- 
sular ligament.  This  is  made  up  of  four  parts :  anterior,  posterior,  internal  lateral, 
and  external  lateral.  The  anterior  is  very  weak,  hence  pus  in  the  joint  is  most  apt 
to  make  its  exit  forwards.  It  is  readily  ruptured  in  dislocations.  The  posterior 
ligament,  though  stronger,  may  also  be  torn.  The  two  lateral  ligaments,  the  outer 
being  the  stronger,  become  tense  when  the  condyle  slips  forward  on  the  articular 
eminence.  In  dislocation  they  remain  attached  to  the  mandible  and  are  not  rup- 
tured (see  Fig.  76). 


THE    FACE. 


67 


Dislocation  occurs  when  the  mouth  has  been  widely  opened  and  the  condyles 
are  forward  on  the  articular  eminences.  Some  sudden  jar  accompanied  by  contrac- 
tion mainly  of  the  external  pterygoid  muscle  causes  the  condyle  to  slip  forward  just 
in  front  of  the  articular  eminences.  The  internal  pterygoids  and  the  superficial  fibres 
of  the  masseter  muscles  aid  in  producing  the  luxation.  As  the  condyle  leaves 
the  articulation  to  jump  forward,  it  will  be  noted  that  it  does  so  by  an  extensive 
movement,  which  is  one  of  rotation  on  a  transverse  axis  passing  across  in  the 
region  of  the  mandibular  foramina.  The  condyle  once  out  of  its  socket  is  kept 
out  by  the  contraction  of  the  temporal,  masseter,  and  internal  and  external  pterygoid 
muscles. 

Reduction  of  Dislocation  of  the  Lower  Jaw. — In  reducing  the  dislocation, 
the  condyles  must  be  depressed  and  pushed  back.  This  can  be  done  by  one  of  two 
ways:  viz.,  the  thumbs  of  the  surgeon,  being  protected  by  wrapping  with  a  towel  or 
bandage,  are  placed  on  the  last  molar  teeth,  and  the  jaw  firmly  grasped  with  the 
fingers  beneath  it.  The  back  part  of  the  jaw  is  then  pressed  downward,  the  chin 
tilted  upward,  and  the  condyles  slid  back  into  place. 


Fig.  77.— Fracture  of  the 


Small  fragment  into  which 
was  inserted  the  geniohyoid 
and  geniohyoglosbus  muscles 


luiihle  through  the  symphysis  (author's  sketch). 


The  other  method  is  to  place  two  corks,  one  on  each  side,  or  a  piece  of  wood, 
transversely,  between  the  last  molar  teeth,  then  raise  the  chin  and  pusl>  it  backward. 

The  undetached  lateral  ligaments  are  put  on  the  stretch  when  the  condyle  is 
luxated  forward.  Lewis  A.  Stimson  believes  that  in  attempting  reduction  the  jaw 
should  first  be  opened  wider  to  relax  these  and  then  pushed  back,  but  we  are 
not  prepared  to  admit  that  so  doing  does  relax  these  ligaments.  He  has,  however, 
shown  that  the  interarticular  cartilage  may  become  displaced  and,  by  filling  up  the 
articular  cavity,  prevent  a  proper  reduction.  In  rare  instances  the  catching  of  the 
coronoid  process  beneath  the  malar  bone  may  hinder  replacement. 

Fractures  of  the  Low^er  Jaw  (Mandible). — Fractures  of  the  lower  jaw 
almost  never  occur  through  the  symphysis;  this  is  on  account  of  its  being  the  thickest 
and  strongest  part  of  the  bone.  When  a  fracture  of  the  anterior  portion  of  the  jaw 
detaches  a  median  piece  a  most  dangerous  condition  is  produced.  The  piece,  if 
sufficiently  loosened  by  the  injury,  is  drawn  back  into  the  throat,  carrying  the  tongue 
with  it  and  tending  to  suffocate  the  patient.  Such  a  case  is  'recorded  by  A.  L. 
Peirson  (review  by  Geo.  W.  Norris,  Amer.  Jour.  Med.  Sciences,  1841,  N.  S.  vol.  i, 
p.  186).  A  man  was  run  over  by  a  wheel  which  passed  over  his  jaw,  fracturing  it 
on  each  side  and  forcing  the  piece  into  his  mouth.  The  piece  was  drawn  backward 
and  nearly  caused  death  from  suffocation. 


68 


APPLIED    ANATOMY. 


In  the  Ajinah  of  Surgery  (vol.  xi.x,  1894,  p.  653)  is  recorded  a  case  of  the 
author's  in  which  a  man,  while  drunk,  fell  and  struck  his  chin  on  the  curbstone.  A 
fracture  was  produced  through  the  symphysis  above  and  branching  to  each  side  of 
the  crenial  tubercle  below.  This  small  median  piece  was  drawn  back  into  the  throat 
nearly  to  the  hyoid  bone,  and  suffocative  symptoms  were  marked.      These  disap- 


Geniohyoid  muscle  Geniohyoglossus  muscle 

Fig.  7S.— Anteroposterior  section  of  the  tongue  and  floor  of  the  mouth ,  near  the  midline. 

peared  when  the  detached  piece  was  drawn  forward  and  wired  in  place.  The  piece 
was  drawn  backward  by  the  geniohyoid  and  geniohyoglossus  muscles.  The  digas- 
trics may  also  have  aided  in  depressing  the  fragment  (Figs.  77  and  78). 

The  most  usual  site  of  fracture  is  in  the  neighborhood  of  the  mental  foramen. 
This  is  located  just  below  the  second  premolar  tooth  (sometimes  between  the  first 
and  second  J.      This  foramen  and   the  large  socket  for    the    canine    tooth    farther 


Masseter  muscle 


Buccinator  muscle 


Fig.  79. — Fracture  of  the  lower  ja 


on  of  the  mental  foramen,  showing  the  lii 
nuscles  in  producing  displacement. 


forward  weaken  the  bone  somewhat  in  this  region.  The  jaw  is  strengthened  behind 
the  mental  foramen  by  the  commencement  of  the  anterior  portion  of  the  ramus  and 
by  an  increase  in  the  size  of  the  mylohyoid  ridge  on  the  inner  surface.  The  jaw  is 
also  protected  by  the  thick  masseter  muscle  and  fracture  is  most  liable  to  occur  just 
in  front  of  it.      This  constitutes  the  typical  fracture  of  the  lower  jaw  (Fig.  79  ). 


THE    FACE. 


69 


Fig.  So.— Fracture  of  the  lower  jaw,  s 
the  line  of  fracture  proceeding  downwj 
backward,  favoring  displacement. 


Displacement. — The  displacement  of  the  fragments  will  depend  on  the  line  of 
fracture ;  and  the  line  of  fracture  may  be  determined  by  the  direction  and  character  of 
the  fracturing  force.  The  line  of  fracture  is  oblique.  It  may  be  oblique  from  above 
down  or  from  without  in.  An  examination  of  the  muscles  attached  to  the  mandible 
will  show  that  the  elevators  of  the  jaw  are  attached  to  it  posteriorly  and  its  depres- 
sors anteriorly.  On  this  account,  when  the  fracture  runs  obliquely  down  and 
forward  there  is  little  or  no  displacement,  because  the  depressors  and  elevators  tend  to 
press  the  fragments  together.  When  the  fracture 
runs  downward  and  backward  (see  Fig.  80),  the 
depressors  and  elevators  tend  to  separate  the 
fragments.  The  depression  of  the  anterior  frag- 
ment is  particularly  marked  when  the  fracture  is 
double,  involving  both  sides  of  the  jaw.  The 
muscles  which  tend  to  depress  the  anterior  frag- 
ment are  the  geniohyoglossus,  geniohyoid,  mylo- 
hyoid (anterior  portion  ),  digastric,  and  platysma. 
The  muscles  which  elevate  the  posterior  frag- 
ment are  the  temporal,  masseter,  buccinator,  and 
internal  pterygoid. 

The  displacement  may  not  only  be  up  and 
down,  but  may  also  be  lateral.  The  line  of  frac- 
ture may  run  from  the  outside  either  inward 
and  backward  or  inward  and  forward.  The  jaw  is  held  in  place  by  its  own  rigidity 
when  intact ;  when  broken,  the  smaller  fragment  is  liable  to  be  pulled  inward  by  the 
muscles  passing  from  it  toward  the  median  line.  These  muscles  are  the  internal 
pterygoid  and  the  mylohyoid.  The  influence  of  the  former  is  more  marked  than  of 
the  latter,  because  the  fracture  frequently  divides  the  mylohyoid,  leaving  a  part  of 
it  attached  to  each  fragment.      When  the  fracture  passes  from  without  inward  and 

backward,  then  there  will  be  little  or  no 
displacement,  because  the  internal  pteiy- 
goid  and  mylohyoid  draw  the  fragments 
together.  (See  Fig.  81.)  When  the 
line  of  fracture  is  from  without  inward 
and  forward,  the  internal  pterygoid  of 
the  injured  side  and  the  mylohyoid  draw 
the  posterior  fragment  inward,  while  the 
internal  pterygoid  of  the  opposite  side 
draws  the  anterior  fragment  outward 
(Fig.  82). 

From  a  consideration  of  the  forego- 
ing facts,  we  see  that  when  there  is  dis- 
placement it  is  because  the  fracture  runs 
from  above  downward  and  backward, 
and  from  without  inward  and  forward. 
The  anterior  fragment  is  displaced  down- 
ward and  the  posterior  fragment  is  dis- 
placed inward. 

Fractures  through  the  region  of  the 
molar  teeth  are  not  particularly  uncom- 
mon, and  this  is  likewise  the  case  with  fractures  obliquely  downward  and  outward 
through  the  angle  of  the  jaw.  In  these  injuries  the  firm  attachment  of  the  masseter 
on  the  external  surface  of  the  jaw  and  the  internal  pterygoid  on  its  inner  prevent 
displacement. 

Fractures  of  the  coronoid  process  are  exceedingly  rare.  In  them  displacement 
is  prevented  by  the  attachment  of  the  temporal  muscle,  which  passes  much  farther 
down  on  the  inside  than  on  the  outside. 

Fractures  of  the  neck  of  the  jaw  are  particularly  serious.  Inserted  into  the 
condyle  and  neck  of  the  jaw  is  the  external  pterygoid  muscle.  When  a  fracture  of  the 
neck  occurs,  this  muscle  pulls  the  upper  fragment  anteriorly  and  tends  to  tilt  its 


Fig.  81. — Fracture  of  the  jaw,  showing  absence  of  d 
placement  when  the  line  of  fracture  runs  fiom  the  msi 
forward  and  outward. 


7° 


APPLIED    ANATOMY. 


inferior  surface  forward.      This  displacement  is  so  marked  that  an  excessi\'e  amount 
of   caUus   is  thrown    out   and  ankylosis   may   result.      This    so    seriously  interferes 


Fig  82.— Fracture  of  the  jaw,  showing  the  action  of  the  internal  pterygoid  and  mj'lohyoid  muscle 
displacement  when  the  line  of  fracture  runs  from  the  outside  forward  and  inward. 


produ 


with  the  use  of  the  jaws  as  to  justify  an  operation  to  remove  or  replace  the  upper 
frao-ment  in  proper  position.  The  injury  is  liable  to  be  overlooked  in  children,  and 
as  they  grow  up  the  deformity  shown  in  Fig.  83  de\'elops. 


Fig.  83.— Deformity  of  the  face  following  ankylosis  due  to  fracture  of  the  neck  of  the  lower  jaw  in  infancy  (from  an 

original  sketch). 

Treatment. — The  lower  jaw  is  held  up  in  place  by  a  bandage,  and  the  upper 
teeth  act  as  a  splint.  Sometimes  the  teeth  or  fragments  are  wired  in  position,  or  an 
interdental  splint  of  gutta  percha  or  other  material  is  used. 


THE    FACE.  71 

Excision  of  the  Condyle  of  the  Jaw. — The  condyle  can  be  removed 
through  an  incision  3  cm.  long,  running  from  in  front  of  the  ear  along  the  lower  border 
of  the  zygoma.  The  temporal  artery  runs  a  centimetre  in  front  of  the  ear  with  the 
auriculotemporal  nerve  posterior  to  it.  By  care  in  recognizing  the  artery,  it  may  be 
saved  and  dragged  posteriorly.  The  soft  parts  on  the  lower  side  of  the  wound  with 
the  parotid  gland  and  facial  nerve  are  pushed  downward.  The  condyle  can  then 
be  dug  out,  care  being  taken  not  to  go  beyond  the  bone  and  wound  the  internal 
maxillarj'  artery. 

Excision  of  the  Mandible. — In  removing  one-half  of  the  mandible,  the 
incision  is  made  from  the  symphysis  along  the  lower  border  of  the  jaw  to  the  angle 
and  thence  upward  as  high  as  the  lobe  of  the  ear.  If  it  is  desired  to  take  extra 
precautions,  the  last  centimetre  of  this  incision,  from  the  lobule  of  the  ear  down,  may 
be  carried  through  the  skin  only.  This  will  prevent  wounding  to  any  great  extent 
the  parotid  gland  tissue,  the  parotid  duct,  and  positively  avoid  injuring  the  facial 
nerve.  The  incision,  however,  is  rather  far  back  to  wound  an)^  large  branch  of  the  duct, 
and  is  too  low  down  to  wound  the  facial  nerve.  If  it  is  desired  to  carry  the  incision 
higher  than  the  lobule  of  the  ear,  it  should  go  through  the  skin  only.  The  facial 
artery  and  vein  will  be  cut  just  in  front  of  the  masseter  muscle.      The  soft  parts. 


Parolid  gland 


including  the  masseter  muscle,  are  raised  from  the  outer  surface.  In  dividing  the 
bone  anteriorly,  it  should  be  done  .5  cm.  outside  the  median  line.  This  will  be 
about  through  the  socket  of  the  second  incisor.  The  object  of  this  is  to  retain  the 
attachments  of  the  geniohyoid  and  geniohyoglossus  muscles  to  the  genial  tubercles, 
and  so  prevent  any  tendency  of  the  tongue  to  fall  back.  The  jaw  is  pulled  out  and 
separated  from  the  parts  beneath,  the  mylohyoid  muscle  being  made  tense.  Care 
should  be  taken  not  to  injure  the  submaxillary  gland,  which  lies  below  the  mylohyoid 
muscle,  and  the  sublingual  gland,  which  lies  above  it.  The  lingual  nerve  is  also  liable 
to  be  wounded  if  the  knife  or  elevator  is  not  kept  close  to  the  bone. 

As  the  detachment  proceeds  posteriorly,  in  loosening  the  internal  pterygoid  and 
the  superior  constrictor,  if  care  is  not  taken,  the  pharynx  may  be  wounded.  The 
bone  still  being  depressed  and  turned  outward,  the  temporal  muscle  is  to  be  loosened 
from  the  coronoid  process  or  else  the  process  is  detached  and  removed  later.  Access 
is  now  to  be  had  to  the  mandibular  foramen  at  the  mandibular  spine  or  spine  of  Spix. 
The  inferior  alveolar  artery  is  then  secured  and,  with  the  nerve  and  sphenomandibular 
ligament,  divided.  The  jaw  can  now  be  well  depressed  and  brought  inward.  The 
temporomaxillary  joint  is  to  be  opened  from  the  front,  ha\-ing  first  cleared  off  the 
attachment  of  the  external  pterygoid  muscle.  There  is  great  danger  of  wounding 
the  internal  maxillary  artery  at  this  stage  of  the  operation.      It  lies  close  to  the  neck 


72 


APPLIED    AXATOMY. 


of  the  jaw,  and  it  is  to  a\'oid  bringing  it  too  close  to  the  bone  that  Jacobson  ad\'ises 
that  the  jaw  be  not  twisted  outward  when  disarticulation  is  being  performed. 

The  distance  between  the  coronoid  process  and  malar  bone  varies  in  different 
individuals.  The  process  may  be  displaced  by  the  tumor  and  thus  prevent  detachment 
of  the  temporal  muscle.  If  so,  the  process  is  divided  i\-ith  forceps  or  saw  and  removed 
after  the  rest  of  the  jaw  has  been  taken  away.      Injury  of  the  temporoma.xillary  \'eins 


Geniohyogl 
Geniohy 
Mylohyoid  muscl 


of  submaxillary- 


\  Facial  artery 

Sublingual  gland 
e-half  of  the  lower  jaw,  showing  the  structures  t 


^posed. 


may  be  a\oided  by  not  going  behind  the  posterior  edge  of  the  ramus,  as  is  also  the 
case  with  the  external  carotid  artery.  Access  to  the  joint  may  be  facilitated  by  drag- 
ging upward  the  parotid  gland,  which  carries  with  it  the  facial  nerve  and  parotid  duct. 


REGION    OF  THE   EYE. 

The  eyeball  rests  in  its  socket,  which  is  hollowed  out  of  the  soft  parts  contained 
in  the  bony  orbit.  It  is  covered  in  front  by  the  /ids,  which,  as  they  slide  over  the 
eye,  are  lubricated  by  the  tears.  These  are  secreted  by  the  lachrymal  gland  at  the 
upper  outer  portion  of  the  orbit,  flow  over  the  eye,  and  are  drained  off  by  the  lacli- 
ryinal  canals  and  sac  to  empty  into  the  nose  through  the  lachrymonasal  duct. 

The  Orbits. — The  orbits  are  large  four-sided  ca\'ities,  pyramidal  in  shape. 
The  orbit  in  an  adult  male  is  about  4  cm.  in  diameter  from  side  to  side,  and  3.5  cm. 
from  abo^'e  downward.  The  depth  is  4.5  cm.  It  is  thus  seen  that  the  orbit  is  wider 
than  it  is  high.  On  receding  into  the  orbit  from  its  bony  edge,  the  roof  arches 
upward  toward  the  brain  to  ^ecei^^e  the  lachrymal  gland,  thus  making  the  up-and- 
down  diameter  slighth'  longer  than  the  trans\-erse. 

The  rim  of  the  orbit  is  ver}'  strong  and  not  readily  broken  by  injuries.  It  is 
formed  by  the  frontal  bone  above,  the  malar  bone  to  the  outside,  the  malar  and  supe- 
rior maxillary  below,  and  the  superior  maxillary  and  frontal  to  the  inside.  The 
inner  (medial)  walls  of  the  two  orbits  are  parallel,  running  distinctly  anteroposte- 
riorly.      The  outer  (lateral)  walls  diverge  at  an  angle  of  about  45°  from  the  inner  ones. 

The  outer  or  lateral  edge  of  the  orbit  is  nearh'  or  quite  a  centimetre  and  a  half 
posterior  to  the  inner  or  medial  edge.  This  fact,  together  with  the  divergence  of  the 
outer  wall,  is  the  reason  that,  in  enucleation  of  the  eye,  it  is  always  tilted  toward  the 
nose,  and  the  scissors  introduced  and  the  nerve  cut  from  the  outer  side. 

The  outer  wall  of  the  orbital  cavity  is  formed  mainly  by  the  broad  flat  surface  of 
the  greater  wing  of  the  sphenoid  bone,  and  is  thick  and  strong.      The  other  three 


REGION    OF   THE    EYE. 


73 


walls,  on  the  contrary,  are  thin  and  weak.  The  thin  orbital  plate  of  the  frontal  bone 
above  is  frequently  fractured  in  puncture  wounds  by  foreign  bodies,  and  the  frontal 
lobe  of  the  brain  injured.      Two  such  instances  have  come  under  the  writer's  care; 


Supra-orbital  notch 


Lachr\mal  groove 
Optic  foramen 


Infra-orbital  sulcus 


The  bony  orbit. 


Infra-orbital  foran 


in  the  first  case,  an  iron  hook  had  penetrated  and  caused  death  from  cerebritis  ;  in 
the  second,  the  wound  was  caused  by  a  carriage  pole.  The  patient  recovered, 
notwithstanding  a  considerable  loss  of  brain  tissue. 


Ethmoidal  cells 
Lachrymal  canal 


Fig.  S7.— Transverse  section  of  the  orbital  and  nasal  cavities  viewed  from  above. 


To  the  medial  side  of  the  inner  wall  are  the  ethmoid  cells,  covered  by  the  thin 
lachrymal  bone  and  the  os  planum  of  the  ethmoid.  They  are  readily  perforated  by 
suppuration  from  within  those   cavities.      The  floor  is  chiefly  formed  by  the  thin 


74 


APPLIED    ANATOMY. 


orbital  plate  of  the  superior  maxilla.  In  operations  involving  the  floor  of  the 
orbit,  care  is  necessar)^  to  avoid  breaking  through  into  the  maxillary  sinus  (antrum) 
beneath. 

At  the  edge  of  the  junction  of  the  outer  and  lower  walls  lies  the  inferioi-  orbital 
(^sphenomaxillary)  Jissiire.  It  runs  fonvard  to  within  1.5  cm.  of  the  edge  of  the 
orbit  and  e.xtends  back  to  the  apex  of  the  orbit,  where  it  unites  with  the  siipej-ior 
orbital  (sphenoidal)  fissure,  which  lies  between  the  roof  and  outer  \^"all  and  extends 
forward  about  one-third  of  the  distance  to  the  edge  of  the  orbit.  The  optic  foramen 
enters  the  apex  of  the  orbit  at  its  upper  and  inner  portion. 

At  the  lower  inner  edge  of  the  orbit  is  the  lachrymal  groove  for  the  lachrymo- 
nasal  duct,  leading  from  the  eye  to  the  inferior  meatus  of  the  nose.  At  the  junction  of 
the  middle  and  inner  thirds  of  the  upper  edge  is  the  supra-orbital  notch.  This  can 
be  felt  through  the  skin.  It  transmits  the  supra-orbital  artery  and  7ierve.  If  a 
complete  foramen  is  present  instead  of  a  notch,  its  location  cannot  be  so  readily 
determined. 

Contents  of  the  Orbit. — The  orbit  is  lined  with  a  periosteum,  and  contains 
the  eyeball,  the  muscles  which  mo\'e  it,   the  \-eins,  arteries,   and  ner\'es  which  go  to 


Superior  oblique  muscle 

Superior  orbitotarsal 

ligament 

Levator  palpebras 

superior  muscle 

Superior  rectus  muscle 
Tarsal  cartilage 


:  rectus  musclt 
Inferior  oblique  musclf 


Capsule  of  Tenon 


Fig.  SS.— Sagittal  section  through  the 


it  together  with  some  which  tra^•erse  the  orbit  to  go  to  the  face,  and  the  lachrymal 
gland.  These  structures  are  more  or  less  surrounded  with  a  fascia  which  is  continu- 
ous with  the  periosteum. 

Periosteum. — The  periosteum  of  the  orbit  is  not  tightly  attached  and  in  cases 
of  disease  can  readily  be  raised  from  the  bone  beneath.  Anteriorly,  it  is  continuous 
at  the  orbital  rim  with  the  periosteum  of  the  bones  of  the  face.  Posteriorly,  it  is  con- 
tinuous through  the  optic  foramen  and  sphenoidal  fissure  with  the  dura  mater. 
It  sends  prolongations  inward,  covering  all  the  separate  structures  in  the  orbit. 
From  the  edge  of  the  orbit  it  stretches  o\-er  to  the  tarsal  cartilages,  forming  the 
superior  and  ^inferior  orbitotarsal  ligaments.  These  form  a  barrier  (called  the  sep- 
ticm  orbitale)  to  the  exit  of  pus  from  within  the  orbit,  and  for  that  reason  it  is  advised 
that  orbital  abscesses  should  be  opened  early.  The  lower  portion,  as  it  reaches 
the  lachrymal  groo\^e,  splits  to  co^'er  the  lachrymal  sac.  Another  extension 
from  above  splits  to  enclose  the  lachrymal  gland,  which  is  seen  to  lie  comparatively 
loose  in  the  upper  outer  portion  of  the  orbit,  sustained  by  its  suspensory  ligament. 
It  then  sends  thin  fibrous  layers  which  cover  the  muscles,  arteries,  veins,  ner\-es,  fat 
pellicles,  and  finally  the  eyeball  posterior  to  the  insertion  of  the  muscles  and  optic 
nerve.      This  last  portion,  called  the  capsule  of  Tenon,  begins  as  far  forward  as  the 


REGION    OF   THE    EYE. 


75 


^<'*-',— -rf^ 


insertion  of  the  recti  muscles  on  their  under  (inner)  side,  passes  over  the  globe  poste- 
riorly, over  the  optic  nerve,  and  blends  with  the  layer  covering  the  deep  surface  of  the 
muscles.  It  is  joined  to  the  sclerotic  coat  of  the  eye  and  dural  sheath  of  the  nerve 
by  a  loose  net-work  of  delicate  fibrils.  This  forms  practically  a  space  lined  with 
endothelial  plates,  similar  to  the  subarachnoid  space  in  the  brain.  The  capsule  of 
Tenon  is  a  distinct,  well  marked  membrane,  and  the  eyeball  lies  loose  and  revolves 
freely  within  it.  It  is  this  space  into  which  the  strabismus  hook  is  put  when  it  is 
desired  to  cut  the  recti  muscles  for  squint.  Fibrous  prolongations  are  also  sent 
to  the  sides  of  the  orbit  from  the  internal  and  external  recti  muscles.  They  are 
the  check  ligaments;  and  one  from  the  inferior  rectus  forms  the  suspensory  ligament 
of  the  eye. 

Affections  of  the  Orbit. — The  orbit  is  often  invaded  by  tumors,  pus,  hemor- 
rhages, and  air  (producing  emphysema). 

Tumors  may  either  originate  in  the  orbital  contents,  as  sarcomas  of  the  lach- 
rymal gland  or  eye,  or  they  may  come  from  surrounding  regions.  It  is  more  rare 
for  them  to  enter  through  the  natural  openings  of  the  orbit  than  it  is  for  them  to 
push  through  its  thin  walls.  Coming  through  natural  openings,  they  may  make 
their  entrance  :   (i)  from  the  brain  through  the  optic  foramen  or  sphenoidal  fissure  ; 

(2)  from  the  region  of  the  zygomatic  and  temporal  fossae  through  the  sphenomaxil- 
lary fissure  ;   (3)  from  the  nasal  cavities 

(as  I  have  seen),  coming  up  the  lachry- 
monasal  canal. 

In  invading  the  orbit  through  its  walls 
they  may  come:  (i)  from  the  nasal  cavi- 
ties and  ethmoidal  cells,  pushing  through 
the  thin  internal  wall;  (2)  from  the  frontal 
sinus,  appearing  at  the  upper  inner  angle; 

(3)  from  the  sphenoidal  cells  at  the  pos- 
terior portion  of  the  inner  wall ;  (4)  from 
the  brain  cavity  above,  breaking  through 
the  roof ;  (5)  from  the  maxillary  sinus 
below,  pushing  through  the  floor. 

Dermoids. — In  thefoetus,  the  fronto- 
nasal process  comes  from  above  down- 
ward to  join  the  maxillary  processes  on 
each  side.  This  leaves  an  orbitonasal  cleft  to  form  the  orbit.  Owing  to  defects  in  the 
development  of  this  cleft,  dermoid  tumors  may  occur  in  its  course.  They  are  seen 
either  at  the  outer  or  inner  angle  of  the  eye.  They  are  more  common  at  the  outer 
angle  near  the  e.xternal  angular  process,  and  may  have  a  prolongation  to  the  dura 
mater.  They  also  occur  at  the  inner  angle  at  the  frontonasal  suture  (Fig.  89).  At 
this  point,  also,  meningoceles  are  liable  to  occur.  As  pointed  out  by  J.  Bland  Sutton 
the  question  of  diagnosis  is  of  importance,  as  an  attempt  to  remove  a  meningocele 
by  operation  is  apt  to  be  followed  by  death,  whereas  a  dermoid,  though  it  may  have 
a  fibrous  prolongation  to  the  dura  mater,  can  be  more  safely  removed. 

Orbital  Abscess. — Suppuration .  may  either  originate  within  the  orbit  or  extend 
into  it  from  the  neighboring  tissues.  If  the  former  is  the  case,  it  may  occur  from 
caries  of  the  bones  of  the  orbit,  as  in  syphilis.  It  may  originate  from  erysipelas 
involving  the  orbit.  General  inflammation  and  suppuration  of  the  eye  may  break 
through  the  eye  and  spread  in  the  orbital  tissues  (panophthalmitis).  If  pus  enters 
the  orbit  from  the  outside,  it  is  usually  from  suppuration  and  caries  of  the  frontal 
sinus  and  ethmoidal  cells.  In  this  case,  the  swelling  shows  itself  at  the  upper 
portion  of  the  inner  angle  of  the  eye.  Pus  in  the  maxillary  sinus  is  most  apt  to 
discharge  into  the  nose,  and  not  break  through  the  roof  into  the  orbit  above. 
Pus  within  the  orbit  tends  to  push  the  eyeball  forward  and  even  distend  the  lids. 
As  the  orbitotarsal  ligament  runs  from  the  bony  edge  of  the  orbit  to  the  lids,  pus 
does  not  find  an  easy  exit.  The  abscess  should  be  opened  by  elevating  the  upper 
lid,  and  incising  the  coniuncti\'a  in  the  sulcus  between  the  globe  of  the  eye  and  the  lid. 
Pus  from  suppuration  of  the  lachrymal  sac  does  not  tend  to  in\-ade  the  orbit  but 
works  its  way  forward  to  the  skin. 


Fi^.  89.— Dermoid  of  orbit.  Boy,  15  years  of  age.  It 
extended  back  to  the  body  of  the  sphenoid  bone.  Case  of 
Dr.  Wm.  Zentmayer. 


76 


APPLIED    ANATOMY. 


Foreign  Bodies  in  the  Orbit. — Owing  to  the  considerable  space  which  exists 
between  the  eye  and  orbital  walls,  large  foreign  bodies  ma\'  find  a  lodgment  there, 
often  producing  serious  symptoms  for  a  considerable  length  of  time.      The  tang  of 


Fig.  90. — Lines  of  the  skin 


operation  for  obta 


;  access  to  ihe  retrobulbar  1 


a  gun  barrel  has  been  so  found.     This  should  lead  one  to  search  for  foreign  bodies 
carefully  when  this  portion  of  the  orbital  contents  has  been  wounded. 


Periosteal  hnnig  of  orbit 


Fig.  91. — The  rim  of  the  orbit  has  been  divided  and  the  p 
through  the  periosteal  lining.     (Kronlein's  operat 


turned  outward  ;  an  incision  is  then  made 
%  access  to  the  retrobulbar  region.) 


Emphysema. — In  cases  of  fracture  involving  the  inner  wall  and  opening  up  the 
nasal  ca\-ities  or  sinuses  the  air,  particularly  in  blowing  the  nose,  may  be  forced  into 


Periosteal  lining 


np  of  rectus  externus  i 
\ 


Rectus  extemus  y 


Fig.  92. — The  edges  of  the  incised  periosteum  have  been  separated  and  the  external  rectus  muscle  divided,  exposing 
the  space  posterior  to  the  bulb.     (Kronlein's  operation  for  obtaining  access  to  the  retrobulbar  region.) 


the  orbit,  distending  the  Hds  and  producing  a  pecuHar  crackHng  sensation  when 
palpated.  No  treatment  directed  to  removal  of  the  air  is  necessary.  It  is  valuable 
as  a  diagnostic  sign  of  fracture  communicating  with  the  nasal  cavities. 


REGION    OF    THE    EYE.  77 

Hemorrhage. — Hemorrhage  into  the  orbit  may  occur  either  as  the  result  of 
direct  traumatism  in\ohing  the  contents,  or  from  fracture  of  the  base  of  the  skull 
through  the  orbital  plate.  The  blood  pushes  its  way  anteriorly  and  shows  itself 
under  the  coniuncti\a  surrounding  the  cornea.  It  is  prevented  from  appearing 
on  the  lids  by  the  orbitotarsal  ligament.  A  subconjunctival  hemorrhage  alone  is  not 
sufficient  to  justify  a  diagnosis  of  fracture  of  the  base  of  the  skull,  although  it  is 
a  significant  confirmatory  symptom. 

Kronlein's  Operation. — In  order  to  gain  access  to  the  back  part  of  the  orbit 
to  remo\'e  tumors,  Kronlein  resects  the  outer  wall,  divides  the  periosteum  and 
external  rectus  muscle,  and  so  gains  access  to  the  retrobulbar  space.  The  various 
steps  of  the  operation  are  shown  in  Figs,  go,  91,  92. 

THE  EYEBALL  AND  OPTIC  NERVE. 

The  eyeball  has  three  main  coats,  viz. :  a  fibrous  outer  coat,  called  the  sclerotic; 
a  vascular  middle  coat,  the  choroid;  and  a  nervous  inner  coat,  the  retina. 

Sclerotic  Coat. — The  sclerotic  coat  forms  a  firm  protective  covering  or  case 
for  the  delicate  retina  within.  It  is  continuous  posteriorly  with  the  fibrous  coat  or 
dura  of  the  optic  nerve,  which  is  a  continuation  of  the  dura  mater  of  the  brain.  At 
the  optic  foramen,  the  dura  mater  splits  into  two  layers;  the  outer  layer  forms  the 
periosteum,  while  the  inner  forms  the  dural  coat  of  the  optic  ner\'e.  This  nerve  also, 
like  the  brain,  has  an  arachnoid  and  a  pial  membrane.  The  sclerotic  coat  is  con- 
tinued forward  o\'er  the  front  of  the  eye  as  the  cornea.  As  it  is  essentially  a  mem- 
brane intended  to  be  protective  in  its  function,  its  diseases  are  those  of  weakness: 
thus,  if  the  cornea  is  affected,  it  bulges  forward  and  is  called  an  anterior  staphyloma  ; 
if  the  posterior  part  is  affected,  the  sclera  is  stretched,  and  it  forms  a  posterior 
staphyloma. 

Anterior  staph^-loma  may  occur  either  rapidly  as  a  small  local  protrusion,  resulting 
from  ulceration  of  the  cornea  or  a  wound,  or  it  may  be  slow  in  forming,  and  involve 
nearly  or  quite  the  whole  of  the  cornea,  pushing  it  forward  in  the  shape  of  a  cone; 
this  is  called  eonical  cornea.  Posterior  staphyloma  occurs  in  near-sighted  people,  the 
anteroposterior  diameter  of  the  eye  being  longer  than  normal.  If  this  posterior 
staphyloma  or  stretching  of  the  eye  becomes  marked,  the  choroid  atrophies  and  the 
functions  of  the  retina  are  lost.  The  white  sclera  is  seen  with  the  ophthalmoscope, 
surrounding  or  to  one  side  of  the  optic  nerve. 

Although  the  cornea  has  no  blood-vessels,  it  still,  from  its  exposed  position, 
becomes  inflamed  {keratitis)  and  ulcerated,  and  e\'entually  blood-vessels  may  de- 
velop into  it  from  its  periphery,  constituting  the  disease  kno^^■n  as  pannus. 

The  weakest  portion  of  the  globe  is  at  the  junction  of  the  sclerotic  coat  with  the 
cornea.  It  is  here  that  the  sclera  is  thinnest.  On  this  account,  blows  on  the  eye 
cause  it  to  rupture  usually  at  this  point,  the  tear  encircling  the  edge  of  the  cornea 
for  a  variable  distance  (usually  at  its  upper  and  inner  quadrant)  according  to  the 
force  and  direction  of  the  injury.      On  healing,  a  staphyloma  may  form  at  this  point. 

The  choroid  or  vascular  coat  of  the  eye  contains  the  pigme^it  or  color  of  the 
eye.  It  is  continued  forward  as  the  ciliary  body  (or  processes)  and  iris.  Being  a 
vascular  tissue,  its  diseases  are  inflammator}-.  If  the  choroid  is  affected  A^"e  ha\'e 
choroiditis;  if  the  ciliary  region  is  inflamed,  it  is  called  cyelitis ;  and  if  the  iris  is 
inflamed  we  ha^'e  iritis. 

The  retina  or  nervous  coat  of  the  eye  is  concerned  in  the  function  of  sight  and 
it,  like  other  ner\'es,  may  be  affected  with  inflammation,  called  retinitis.  Sometimes 
it  becomes  loosened  from  the  choroid  beneath  by  a  hemorrhage  or  rapid  stretching 
of  the  sclera,  constituting  a  detachment  of  the  retina.  Outside  the  disk  is  the  macula 
lutea  and  fovea  centralis  or  region  of  distinct  \'ision. 

Filling  the  interior  of  the  eye  is  the  jelly-like  transparent  vitreous  humor,  enclosed 
in  the  hyaloid  membrane.  In  front  of  the  \'itreous  humor  is  the  lens ;  and  the  clear, 
limpid  liquid  between  the  anterior  surface  of  the  lens  and  the  posterior  surface  of  the 
cornea  is  the  aqueous  humor. 

The  lens,  immediately  behind  the  iris,  is  suspended  in  its  capsule  from  the 
ciliary  processes  by  its  suspensorv  ligament  or  zone  of  Zinn.  Between  the  ciliary 
processes  and  the  sclera  lies  the  ciliary  muscle,  which  regulates  the  accommodation 


78 


APPLIED    ANATOMY. 


or  focussing  power  of  the  eye.  The  ciHary  processes  are  formed  of  convoluted 
blood-vessels  supported  by  connective  tissue  and  covered  by  the  pigmented  exten- 
sion of  the  retina.  This  ciliary  region  is  an  exceedingly  sensitive  one  and  a  serious 
wound  of  it  usually  means  a  loss  of  the  eye. 

Catai'ad. — When  the  lens  is  opaque  it  constitutes  the  disease  known  as  cata- 
ract: this  name  is  also  applied  to  opacities  of  the  capsule  of  the  lens.  When  the  lens 
alone  is  opaque  it  is  called  a  lenticular  cataract;  when  the  capsule  alone  is  affected,  it 
is  a  capsular  cataract.  Both  are  sometimes  involved,  constituting  a  lenticulocapsidar 
cataract.  The  lens  is  made  up  of  layers  like  an  onion.  Some  of  these  layers  may 
become  opaque,  leaving  a  surrounding  rim  of  clear  tissue.  The  nucleus  within  the 
affected  layer  is  also  clear.  This  form  is  called  a  zonular  or  lamellar  cataract.  A 
capsular  cataract  may  affect  the  anterior  portion  of  the  capsule,  forming  an  anterior 
polcvr  cataract,  or  the  posterior  layer  of  the  capsule,  forming  a  poste7'ior  polar  cataract. 

If  the  cornea  has  been  perforated  by  a  central  ulceration,  the  aqueous  humor 
escapes,  the  lens  falls  forward,  and  its  anterior  capsule  becomes  adherent  at  the  site 


Suspensory  ligament  of  lens 
Canal  of  Scilemm 
Ciliary  process 
Conjunctiva 


Cornea 

Anterior  chamber 
Iris 

Posterior  chamber 

Sclerocorneal  juncture 


Tendon  of  in- 
ternal rectus 
muscle 

Vena  vorticosa 


Hyaloid 

Optic 

Central  retinal  \ 


,/yj   /        Optic  papilla 
.  93. — Diagrammatic  honzont-^l  section  of  right  eye 


Rttiua 
centralis 

X  3^2.     (Piersol.) 


of  perforation.  As  the  aqueous  humor  reaccumulates,  it  pushes  the  lens  back,  leaving 
a  small  portion  of  inflammatory  tissue  clinging  to  its  anterior  capsule,  thus  forming 
an  anterior  polar  cataract.  A  posterior  polar  cataract  is  the  result  either  of  disease, 
such  as  choroiditis,  in  which  the  posterior  capsule  becomes  involved,  or  of  a  persistence 
of  the  remains  of  the  hyaloid  a?'tery,  a  fetal  structure. 

Secondary  cataracts  are  the  opacities  of  the  capsule  or  inflammatory  bands 
and  tissues  which  are  left,  or  which  occur,  after  the  removal  of  the  lens.  The  lens  in 
childhood  is  soft;  it  grows  harder  as  age  increases.  If  the  aqueous  humor  obtains 
access  to  the  lens  through  a  wound  of  the  anterior  capsule,  the  lens  becomes  opaque, 
constituting  a  traumatic  catai'act.  In  operating  for  cataract  in  childhood,  the  lens, 
being  soft,  is  first  rendered  opaque  by  the  aqueous  humor  admitted  through  a 
puncture  made  in  the  capsule  ;  if  it  is  admitted  repeatedly  to  the  lens  by  the 
surgeon's  needle  (needhng  or  discission  operation)  the  lens  matter  is  completely 
dissolved.  The  fluid  lens  matter  can  also  be  remo\'ed  by  a  suction  instrument. 
In   old   people  the  nucleus  becomes  hard  and  opaque,  forming  a  senile  cataract. 


REGION    OF   THE    EYE.  79 

The  aqueous  humor  does  not  dissolve  the  opaque  lens  after  the  age  of  thirty- five 
years.  Senile  cataract  rarely  occurs  before  the  forty-fifth  year,  so  there  is  a  period 
of  ten  years  in  which  a  cataract  may  be  a  nuclear  cataract  without  being  senile. 

To  remove  a  nuclear  or  a  senile  cataract,  a  slit  is  made  through  the  cornea  near 
its  scleral  junction,  a  piece  of  the  iris  may  (or  may  not)  be  removed,  the  anterior 
capsule  is  cut  with  a  cystotome  and  the  opaque  lens  pressed  out  through  the 
opening  so  made,  then  through  the  pupil  (either  artificial  or  dilated  with  atropine), 
and  finally  through  the  sclerocorneal  incision.  The  posterior  capsule  is  not  injured, 
and  it  prevents  the  vitreous  humor  from  escaping.  If  inflammation  follows  the 
operation,  the  iris  and  ciliary  region  throw  out  lymph  and  the  remains  of  the 
capsule  become  opaque,  forming  a  secondary  or  capsular  cataract.  This  is  removed 
by  tearing  or  cutting  it  across  with  needles  or  extremely  fine  scissors. 

Iris. — The  iris  is  the  continuation  of  the  choroid  through  the  ciliary  body,  and 
extends  down  to  the  pupil,  its  free  edge  resting  on  the  anterior  surface  of  the  lens. 
The  iris  is  composed  of  a  vascular  and  fibrous  anterior  portion,  and  a  muscular  and 
pigmented  posterior  portion.  In  consequence  of  its  vascularity,  the  iris  is  the  fre- 
quent site  of  inflammation.  When  inflamed  it  pours  out  lymph  which  may  cause  it 
to  adhere  to  the  lens  behind,  forming  a  posterior  sjmechia.  An  anterior  synechia  is 
where,  on  account  of  a  perforation  of  the  cornea,  the  iris  washes  forward  and  becomes 
attached  to  the  cornea  in  front. 

The  circular  muscle  fibres  surrounding  the  pupil  are  anterior,  and  form  the 
sphincter  pupillcB  muscle;  it  contracts  the  pupil.  The  radiating  muscular  fibres, 
which  lie  posteriorly,  form  the  dilator  pupillcB  ;  it  dilates  the  pupil.  The  dark  pig- 
ment layer  is  on  the  posterior  surface  of  the  iris,  and  after  an  attack  of  iritis,  as  the 
adherent  iris  is  torn  loose  from  the  lens,  it  leaves  patches  of  pigment  adhering  to  the 
anterior  capsule. 

The  iris,  as  it  rests  at  its  pupillary  margin  on  the  lens,  divides  the  space  anterior 
to  the  lens  into  two  parts.  The  part  between  the  posterior  surface  of  the  iris  and  the 
anterior  surface  of  the  lens  forms  the  posterior  chamber.  The  anterior  chamber  lies 
between  the  anterior  surface  of  the  iris  and  the  posterior  surface  {Descemet' s  mem- 
bra7ie)  of  the  cornea.  The  two  chambers  communicate  through  the  pupil.  The 
anterior  surface  of  the  iris  toward  its  periphery  is  of  the  nature  of  a  coarse  mesh- 
work,  the  spaces  of  which  are  the  spaces  of  Fontana.  They  communicate  with  a 
venous  or  lymph  canal  which  passes  around  the  eye  at  the  sclerocorneal  junction 
{canal  of  Schlemm ). 

Aqueous  Humor  and  Anterior  Lymph  Circulation. — The  aqueous  humor 
is  of  the  nature  of  lymph.  It  is  secreted  by  the  ciliary  processes  and  posterior  surface 
of  the  iris.  It  passes  through  the  pupil  to  the  anterior  chamber,  and  enters  the 
spaces  of  Fontana  to  empty  into  the  canal  of  Schlemm.  The  canal  of  Schlemm 
empties  its  contents  into  the  anterior  ciliary  veins.  In  iritis  and  glaucoma  the  13'mph- 
current  is  seriously  interfered  with.  In  iritis,  the  swelling  and  outpouring  of  lymph 
blocks  the  spaces  of  P'ontana  and  prevents  a  free  e.xit  of  the  aqueous  humor  from 
the  anterior  chamber,  therefore  in  this  condition  the  anterior  chamber  is  deep,  and 
the  iris  is  seen  to  lie  far  beneath  the  cornea. 

Glaucoma. — Glaucoma  is  a  disease  accompanied  by  increased  intra-ocular 
tension.  The  eyeball  feels  hard  to  the  touch.  It  is  supposed  to  be  due  to  disease 
of  the  ciliary  region  interfering  with  the  canal  of  Schlemm  and  obstructing  it. 
Therefore,  the  drainage  of  the  eye  and  the  circulation  of  the  aqueous  humor  is  inter- 
fered with.  In  iritis  the  anterior  chamber  becomes  deeper,  but  in  glaucoma,  as  the 
intra-ocular  tension  increases,  it  pushes  the  lens  forward,  and  it  is  seen  to  lie  close 
up  to  the  cornea;  so  that  a  shallow  anterior  chamber  causes  the  ophthalmologist  to 
suspect  glaucoma  and  a  deep  anterior  chamber  iritis.  The  increased  pressure  within 
the  eye  pushes  the  optic  nerve  backward  at  its  point  of  entrance,  so  that  it  is  seen 
sunk  below  the  surface  of  the  adjoining  retina,  forming  a  distinct  cup-shaped  cavity 
or  pit.      This  is  cupping  of  the  disk. 

Optic  Nerve. — The  optic  nerve  reaches  from  the  optic  chiasm  to  the  eyeball,  a 
distance  of  about  5  cm.  (2  in.).  It  enters  the  apex  of  the  orbit  through  the  optic  foramen 
at  t)ie  upper  inner  angle,  in  company  with  the  ophthalmic  artery.  The  artery  crosses 
the  under  surface  of  the  nerve  from  its  inner  to  its  outer  side.     The  optic  nerve  has 


8o 


APPLIED    ANATOMY. 


as  its  covering  a  prolongation  of  the  membranes  of  the  brain.  The  dura  mater 
when  it  reaches  the  foramen  sphts  and  gives  one  layer  to  form  the  periosteum  lining 
the  orbit  and  the  other  to  form  a  fibrous  sheath  of  the  nerve.  This  arrangement 
prevents  pus,  forming  in  the  orbit,  from  passing  through  the  optic  foramen  into 
the  skull.  The  arteria  centj-alis  retince  enters  the  nerve  on  its  under  side  and  passes 
through  its  centre  to  the  interior  of  the  eye.  The  nerve  itself  is  covered  with  a  fine 
pial  membrane  and  an  arachnoid  separating  it  from  the  dura,  thus  forming  subdural 
and  subarachnoid  spaces.  As  these  membranes  and  spaces  are  continuous  with  those 
of  the  brain,  hemorrhage  or  serous  effusions  occurring  within  the  brain  can  thus  find 
their  way  into  the  sheath  of  the  nerve. 

As  the  nerve  enters  the  eye,  it  is  contracted  and  forms  the  optic  disk  or  papilla. 


Cornea 


Greater  arterial 


Lesser  arteria!  rin 


Canal  of  SchL 

•  Corneal  loop 


Communication  betwv^.. 

choroidal  and  optic 
Central  retina!  '~ 


Long  posterior  ciliary  artery 
Communicating  twig 
Inner  sheath  vessels 
Outer  sheath  vessels 


It  is  readily  seen  with  the  ophthalmoscope  as  a  round  spot  somewhat  lighter  in  color 
than  the  surrounding  eyeground.  Coming  from  a  depression  or  cup  in  the  disk, 
called  the  porus  opticus,  are  the  retinal  arteries  and  veins.  A  certain  amount  of 
cupping  is  normal,  but  if  wide  and  deep,  with  overhanging  edges  over  which  the 
vessels  can  be  seen  to  dip,  it  is  indicative  of  glaucoma. 

Sometimes  the  papilla  or  disk  is  swollen,  constituting  an  optic  neu7'iiis. 
In  brain  tumor  this  is  frequently  the  case  and  is  called  choked  disk,  or  "stamtng- 
papilla,"  so  named  because  the  circulation  was  thought  to  be  interfered  with  owing 
to  the  intracerebral  pressure  being  transmitted  directly  to  the  nerve.  On  the  sub- 
sidence of  a  severe  neuritis  the  nerve  is  left  in  a  state  of  optic  atrophy  and  blindness 
is  the  result. 


Fig.    95.      NORMAL    HUMAN    FUNDUS    OCULI,  SHOWING    OPTIC    PAPILLA   AND    BLOOD    VESSELS;    ALSO   THE    MACULA    LUTEA. 

Drawn  by  Mr.  Louis   Schmidt. 


REGION    OF    THE    EYE. 


8i 


Muscles  of  the  Orbit.  —  Six  muscles  are  connected  with  the  eyeball, 
four  straight  and  two  oblique.  One  muscle,  the  levator  palpebrce,  goes  to  the 
lid.  The  four  recti  muscles,  superior,  inferior,  external,  and  internal,  arise  from  a 
common  tendinous  origin,  forming  a  ring  or  tube  called  the  ligametit  of  Zi7in. 
This  lio-ament  or  tube  surrounds  the  optic  foramen  and  is  attached  to  the  opposite 
side  of  the  sphenoidal  fissure.  Through  it  run  the  optic  nerve  and  ophthalmic  artery, 
the  third,  fourth,  and  the  nasal  branch  of  the  ophthalmic  (fifth;  nerve. 

The  levator  palpcbrcB  and  superior  oblique  arise  to  the  inner  side  and  above  the 
optic  foramen  close  to  the  origin  of  the  other  muscles.  The  superior  oblique,  after 
passing  through  its  trochlea  or  pulley  at  the  inner  upper  angle  of  the  orbit,  continues 
downward,  backward,  and  outward  between  the  superior  rectus  and  the  eye,  to  be 
inserted  above  the  extremity  of  the  inferior  oblique. 


sphenoidal  sinus 


Levator  palpebras 
superior  muscle 


Superior  ophthal- 


Lachrymal  gland 


Fig.  96. — The  roof  of  the  orbit  has  been  removed,  showing  the  contents. 

The  inferior  oblique  arises  from  the  anterior  edge  of  the  orbit  just  to  the  outer 
side  of  the  lachrymal  groove.  It  passes  outward,  upward,  and  backward,  over 
the  external  surface  of  the  inferior  rectus,  to  be  inserted  beneath  the  external  rectus. 

The  recti  muscles  insert  into  the  sclera  5  to  7  mm.  back  from  the  cornea.  In 
the  operation  for  internal  squint  or  strabismus,  the  internal  rectus  muscle  is  cut. 
It  possesses  the  longest  tendon  of  insertion,  while  the  external  possesses  the  shortest. 
The  recti  muscles  pull  the  eyes  toward  their  respective  sides.  The  superior  oblique 
turns  the  cornea  down  and  out  and  rotates  it  inwardly.  The  inferior  oblique  turns 
the  cornea  up  and  slightly  out  and  rotates  the  eye  outward.  A  disarrangement  of  any 
of  these  muscles  produces  diplopia  or  double  vision. 

Blood-Vessels  of  the  Orbit. — The  arteries  of  the  orbit  are  derived  from  the 
ophthalmic  artery,  which  breaks  up  into  its  various  branches  soon  after  it  passes  through 
the  optic  foramen.  In  enucleation  of  the  eye  there  is  practically  no  bleeding, 
because  the  arteria  centralis  is  the  only  one  divided,  and  it  is  small.  In  evisceration, 
or  cleaning  out  of  the  contents  of  the  orbit,  the  main  trunk  of  the  ophthalmic  will 
not  be  cut  unless  the  ^•ery  apex  is  invaded.  Hemorrhage  is  readily  controlled  by 
packing  gauze  into  the  orbital  cavity. 

The  veins  of  the  orbit  are  the  superior  and  inferior  ophthalmic.  The  former  is 
much  the  larger  and  more  important.  It  not  only  drains  the  upper  portion  of  the 
orbit,  but  communicates  directly  with  the  angular  branch  of  the  facial,  at  the  inner 
canthus  of  the  eye.  The  infection  of  erysipelas  sometimes  travels  along  these  veins 
directly  from  the  nose,  face,  and  scalp  without,  to  the  cavernous  sinus  and  meninges 
6 


82  APPLIED    ANATOMY. 

within,  causing  thrombosis  and  death.  The  inferior  ophthalmic  usually  empties  into 
the  superior;  its  anastomoses  at  the  anterior  portion  of  the  orbit  with  the  veins  of 
the  face  are  much  smaller  and,  therefore,  not  nearly  so  dangerous. 

Nerves  of  the  Orbit. — The  optic  nerve  is  the  nerve  of  sight.  Interference 
with  it  produces  blindness.  The  oculomotor  or  third  nerve  supplies  all  the  muscles 
of  the  orbit  except  the  external  rectus  and  superior  oblique.  If  paralyzed,  the  eye 
cannot  be  mo\'ed  upward,  inward,  or  to  any  extent  downward.  There  will  be  ptosis 
of  the  upper  lid  from  paralysis  of  the  levator  palpebrae,  and  dilatation  of  the  pupil  and 
paralysis  of  the  accommodation  of  the  eye.  If  the  sixth  or  abdticens  is  paralyzed,  the 
eye  cannot  be  turned  outward.  If  the  fourth  or  pathetic  is  paralyzed,  the  superior 
oblique  fails  to  act,  and  the  double  vision  produced  is  worse  when  the  patient  looks 
down,  because  it  is  normally  a  depressor  muscle.  The  lachrymal,  frontal,  and  nasal 
brajiches  of  the  fifth  are  nerves  of  sensation,  hence,  in  supra-orbital  neuralgia  and  that 
affecting  the  nasal  branch,  pain  is  felt  in  the  orbit  at  the  inner  angle  of  the  eye  and 
down  the  side  of  the  nose. 

Retina. — On  the  interior  of  the  eye,  the  expansion  of  the  optic  nerve  forms  the 
retina.  The  retina  is  divided  into  two  lateral  halves,  each  supplied  by  a  corre- 
sponding half  of  the  optic  ner\'e.  When  the  nerve  reaches  the  optic  chiasm  it  splits 
into  two  parts,  one  (internal  fibres)  going  to  the  opposite  side  of  the  brain,  and 
the  other  (external  fibres)  to  the  ganglia  on  the  same  side  of  the  brain.  Posterior 
to  the  chiasm,  the  ner\-e  fibres  form  the  optic  tracts.  The  optic  tracts,  after  leaving 
the  chiasm,  wind  around  the  crura  cerebri  to  the  external  geniculate  bodies,  thence 
they  pass  to  the  thalami  and  anterior  corpora  quadrigemina,  and  are  continued  back- 
ward into  the  cuneus  lobule  of  the  occipital  lobe  of  the  brain. 

It  will  thus  be  seen  that  a  lesion  affecting  any  portion  of  the  optic  pathway  pos- 
terior to  the  chiasm  will  produce  blindness  of  one-half  of  the  retina  of  both  eyes  on 
the  side  of  the  injury;  a  right-sided  lesion  will  produce  blindness  of  the  right  half  of 
both  retinse,  and  a  lesion  on  the  left  side,  blindness  of  the  left  half  of  both  eyes.  This 
is  called  hemia7topia.  It  is  right  lateral  hcmianopia  if  the  right  half  of  the  visual  fields 
is  affected,  and  left  lateral  if  the  left  sides  are  affected.  Affections  of  the  optic  nerve 
produce  total  blindness  of  that  eye  if  the  whole  nerve  is  involved.  If  only  a  part  is 
involved,  then  a  unilateral  hemianopia  may  ensue.  A  bitemporal  hemianopia  may  be 
caused  by  a  tumor  involving  the  anterior  or  middle  portion  of  the  chiasm.  A  binasal 
hemianopia  requires  a  symmetrical  lesion  on  the  outer  side  of  both  optic  nerves  or 
tracts.  A  brain  tumor  located  in  the  cuneus  lobule  would  cause  a  lateral  hemianopia  of 
the  same  side,  right  or  left,  of  both  visual  fields,  hence  sometimes  called  homonymous. 

The  Eyelids  and  Conjunctiva. — The  eyelids  are  composed  of  five  layers, 
viz:  (^i)  skin,  (2)  subcutaneous  tissue,  (3)  orbicularis  palpebj-armn  viuscle,  (4) 
tarsal  cartilage  with  the  contained  J\/eibomiafi  glands,  (5)  the  conjunctiva.  The 
juncture  of  the  two  lids  at  each  end  is  called  the  inner  and  outer  canthus. 

The  skin  of  the  lids  is  thin  and  the  subcutaneous  tissue  loose  and  devoid  of  fat. 
For  these  reasons  blood  finds  its  way  readily  into  the  lids  and  shows  plainly  beneath  the 
skin,  constituting  the  familiar  "black  eye."  The  skin  lends  itself  readily  to  plastic 
operations,  as  it  is  easily  raised  and  the  gap  left  can  be  readily  closed.  The  blood 
supply  of  the  lids  is  abundant,  so  that  the  flaps  are  well  nourished  and  sloughing  is 
not  apt  to  occur.  The  folds  in  the  skin  run  parallel  to  the  edge  of  the  lids,  therefore 
the  incisions  should  be  made  as  much  as  possible  in  the  same  direction.  The 
orbicularis  palpebrarum  muscle  passes  circularly  over  the  lids  and  lies  on  the  tarsal 
cartilage  toward  the  edge  of  the  lids  and  on  the  orbitotarsal  ligament  above.  The  so- 
called  tarsal  cai'tilage  or  plate  is  composed  of  dense  connective  tissue  and  contains  no 
cartilage  cells.  It  is  attached  externally  by  the  external  (^lateral)  palpebral  ligame7it 
and  internally  by  the  internal  (inedial)  palpebral  ligament  or  tendo-oculi.  This  latter 
passes  in  front  of  the  lachrymal  sac.  The  tarsal  plate  is  continued  to  the  rim  of  the 
orbit  by  the  orbitotarsal  ligament  or  septum  orbitale.  The  expansion  of  the  levator 
palpebrae  muscle  ends  in  the  upper  edge  of  the  tarsal  cartilage  and  sends  some  fibres 
to  the  tissues  immediately  in  front.  The  orbitotarsal  ligament  and  tarsal  cartilage 
prevent  the  fat  of  the  orbit  from  protruding  and  also  act  as  a  barrier  to  the  e.xit  of  pus. 

The  tarsal  cartilage  contains  the  Meibomian  glands.  These  can  be  seen  in  life, 
by  everting  the  lid,  as  yellow  streaks  passing  backward  from  the  edge  of  the  lids. 


REGION    OF   THE    EYE. 


83 


Frequently  these  glands  become  obstructed  and  their  mucus  contents  dilate  the 
gland,  forming  a  cyst  known  as  chalazion.  Suppuration  may  occur  and  pus  instead 
of  mucus  is  then  contained  within  them.  The  wall  of  these  cysts  is  formed  by 
fibrous  tissue  containing  some  of  the  epithelial  cells  of  the  glands;  therefore,  if  an 
uninflamed  cyst  is  simply  opened  and  its  contents  expressed,  it  will  soon  reform. 
To  prevent  this  recurrence,  the  lining  membrane  is  curetted  in  order  to  remove  the 
mucus-forming  cells.  The  cyst  may  point  and  be  opened  either  on  the  side  of  the 
skin  or  conjunctiva,  preferably  the  latter. 

The  openings  of  the  Meibomian  ducts  are  on  the  inner  edge  of  the  lids  where 
the  conjunctiva  joins  the  skin.  At  the  outer  edge  of  the  lids  are  the  cilia:  or  eye- 
lashes and  connected  with  them  are  sebaceous  and  sweat  glands.      Infection  of  these 


Subcutaneous  tissue 
/  Orbicularis  palpebrarum 

Fat 


Glands  of  MoU  Cilia  'Ciliarj'  muscle 

Fig.  97. — Vertical  section  of  upper  eyelid  of  child.    X  15.     (Piersol.) 


glands  produces  a  small  abscess  called  a  stye.  As  they  are  on  the  outer  edge  of  the 
lids  they  tend  to  discharge  anteriorly  and  not  toward  the  conjunctiva. 

The  cbnjji-nciiva  covers  the  outer  surface  of  the  eye  and  the  inner  surface  of 
the  lids.  The  fold  where  it  passes  from  one  to  the  other  is  called  the  fornix.  The 
tarsal  or  palpebral  conjunctiva  adheres  closely  to  the  tarsus  and  as  it  is  transparent 
the  Meibomian  glands  can  readily  be  seen  through  it.  The  ocular  or  bulbar  con- 
jimctiva  is  loosely  adherent  to  the  sclerotic  coat  and  through  it  the  conjuncti\'al  vessels, 
which  move  with  it,  can  be  seen.  The  straight  vessels  going  toward  the  cornea  do 
not  move  when  the  conjunctiva  is  moved,  because  they  lie  deeper  and  are  attached  to 
the  sclera. 

The  Lachrymal  Apparatus. — The  lachrymal gla7id  consists  of  two  portions: 
an  orbital  or  superior  portion    and  a  palpebral   or  inferior  portion.      The  orbital 


84 


APPLIED    ANATOMY. 


portion  is  enclosed  in  a  capsule  and  slung  from  the  orbital  margin  by  its  suspensory 
lio-ament.  Beneath,  it  rests  on  the  fascial  expansion  of  the  levator  palpebrae  muscle. 
The  palpebral  portion  is  smaller  than  the  orbital  and  is  partially  separated  from  it  by 
the  fascial  expansion.  It  lies  on  the  conjunctiva  at  the  upper  and  outer  portion  of 
its  forni.x.  The  lachrvmal  gland  opens  by  se\'eral  fine  ducts  into  the  fornLx  of 
the  conjunctiva.  It  is  sometimes  the  seat  of  malignant  tumors,  but  rarely  of  other 
troubles.  The  remaining  lachr3-mal  passages  running  from  the  eye  to  the  nose  are 
frequently  the  seat  of  inflammation,  causing  suppuration  and  obstruction. 

Th&pioida  lachrymalia  in  the  top  of  each  papilla  lead  into  the  canalicidi.  These 
enter  the  lids  perpendicular  to  their  margin  and  turning  at  right  angles  join  just 
before  entering  the  upper  end  of  the  lachrymal  sac. 

The  lacluymal  canal,  embracing  the  sac  and  lachrymonasal  duct,  each  about , 
12  mm.  in  length,  extends  from  just  abo\-e  the  internal  tarsal  ligament  or  tendo  oculi 
to  the  inferior  meatus  of  the  nose.  The  sac  is  strengthened  posteriorly  by  the  tensor 
tarsi  or  muscle  of  Horner,  which  passes  from  the  lachrymal  bone  to  the  pitncta,  and 
by  some  fibres  of  the  palpebral  ligament.  Anteriorly  is  the  strong  palpebral  liga- 
ment. Below  the  palpebral  ligament,  the  sac  is  comparatively  weak  and  here  it  is 
that  distention  occurs  and  pus  makes  its  exit.  The  duct  lies  in  the  lachrymal  groove 
in  the  bone.     It  is  narrower  than  the  sac,  being  3  to  4  mm.  in  width,  and  is  the  usual 


Canaliculcus 
Punctum 

Lachr%-mal  sac 

Lachrymonasal  duct 


Inferior  turbinate 


Fig.  9S. — Lachrymal  apparatus. 

seat  of  obstructions.  To  keep  the  passage  open  in  case  of  stricture  probes  are 
passed.  The  direction  of  the  duct  is  slightly  outward  and  more  markedly  backward, 
being  indicated  approximately  by  a  line  drawn  from  the  inner  canthus  to  just  behind 
the  second  premolar  tooth.  In  probing  the  duct  it  is  customary  to  first  open  the 
punctum  in  the  lower  lid — which  is  normally  only  one  mm.  in  size — by  slitting  it  and 
the  caniculus  with  a  Weber's  canaliculus  knife.  The  probe  is  directed  horizontalh- 
until  the  sac  is  entered,  which  is  recognized  by  the  end  of  the  probe  striking  the 
bone;  it  is  then  raised  vertically  and  passed  downward  and  backward  and  sometimes 
slightly  outward  until  it  can  be  seen  in  the  inferior  meatus  of  the  nose  about  i  cm. 
behind  the  anterior  end  of  the  inferior  turbinated  bone. 


THE   EAR. 

The  external  anditoiy  meatus,  the  tympanum,  and  the  Eustachian  tube  are  the 
remains  of  the  first  branchial  cleft  in  the  foetus.  A  failure  of  any  portion  of  the  cleft 
to  close  normally  may  leave  small  sinuses  or  depressions  in  the  neighborhood  of  the 
ear.  The  external  ear,  also  called  the  auricle  or  pinna,  is  composed  mainly  of  a 
cartilaginous  framework  co\-ered  with  thin  skin;  the  lobe  or  lobule  forms  its  lower 
part  and  is  composed  of  dense  connective  tissue  containing  fat.  The  large  concav- 
itv  leading  into  the  meatus  is  the  concha.     The  skin  of  the  ear  is  thin  and  moder- 


THE    EAR. 


ately  firmly  attached  to  the  cartilage.  The  subcutaneous  tissue  contains  little  or 
no  fat.  .Although  well  supplied  with  blood,  the  exposed  condition  of  the  blood-vessels 
renders  the  ear  sensitive  to  cold,  and  frost-bites  are  common.  Injuries  and  wounds 
of  the  cartilage  are  slow  to  heal,  and  if  inflamed  the  cartilage  becomes  exceedingly 
sensitive.  Swelling  of  the  ear  readily  occurs  from  injury  or  erysipelas,  and  the  tension 
is  quite  painful. 


Helix 
Fossa  scaphoidea 


Fig.  99. — The  external  ear. 

HcEmatoina  auris,  or  effusions  of  blood,  occur  from  traumatism,  especially  in  the 
insane.  While  a  hsematoma  may  occur  between  the  skin  and  perichondrium,  on 
account  of  the  firm  binding  of  the  skin  to  the  cartilage  it  is  usually  between  the 
perichondrium  and  cartilage. 

Angioma,  or  enlargement  of  the  blood-vessels,  not  infrequently  affects  the 
external    ear   and   may  not   only   be   disfiguring   but,    by  showing   a    tendency   to 


Chorda  tympani 
Facial  1 


Internal  auditory-  meatus 
Semicircular  canals 


-\'ertical  section  of  the  right 


extension,  may  demand  operation.  The  external  ear  derives  its  blood  supply  from 
the  auricular  Jaranches  of  the  temporal,  internal  maxillary,  posterior  auricular,  and 
occipital  arteries.  As  these  are  all  branches  of  the  external  carotid,  that  artery  is 
sometimes  tied  as  a  preliminary  step  to  excising  the  angiomatous  vessels. 

The   External   Meatus. — The    external   auditory    meatus  extends   from    the 
concha  to  the  drumhead,  and  is  about  2.5  cm.  in  length.      A  little  less  than  one-half 


86  APPLIED    ANATOMY. 

of  it  is  cartilaginous  and  a  little  over  one-half  bony.  Viewed  anteroposteriorly  the 
canal  has  a  slight  curve  with  its  convexit)'  upward  (Fig.  loo).  Viewed  from  above 
(Fig.  loi  ),  it  is  seen  first  to  pass  backward  and  then  forward,  forming  an  angle  before 
the  bony  wall  is  reached.  In  order  to  look  into  the  ear  and  see  the  membrane  it  is 
necessary  to  straighten  the  canal,  either  by  inserting  a  speculum  or  by  pulling  the 
auricle  outward,  upward,  and  backward.  In  children,  upward  traction  is  not  so 
necessary  as  in  the  adult.  The  length  of  the  canal  is  approximately  the  same  in  child- 
hood as  in  adults,  but  the  bony  part  is  still  in  a  cartilaginous  condition.  The  external 
opening  is  oval,  while  farther  in  the  canal  is  more  circular;  hence  the  Gruber  speculum, 
which  is  oval  in  shape,  or  the  round  speculum  of  Wilde  can  be  used  with  almost 
equal  satisfaction.  The  point  of  junction  of  the  bony  and  cartilaginous  parts  is 
narrower  than  either  end,  and  it  is  difficult  to  remove  a  foreign  body  which  has ' 
passed  this  point.  This  is  particularly  true  in  children,  the  lumen  of  the  external 
meatus  being  quite  small  and  narrow  while  the  tympanic  membrane  is  nearly  as 
large  as  in  adults. 

The  floor  is  longer  than  the  roof,  owing  to  the  drum  membrane  inclining  at  an 
angle  of   140  degrees.      Cartilage  forms  the  lower  part  of  the  canal,  while  the  upper 


Intarnal  auditory  meatus 


part  is  completed  by  a  fibrous  membrane.  Below  and  in  front  is  the  temporomaxillary 
joint,  and  just  posterior  is  'dx^  glenoid  lobe  of  the  parotid  gland.  When  the  gland  is 
inflamed  and  swollen  it  presses  on  the  cartilaginous  canal  and  produces  pain;  and 
in  cases  of  suppuration  pus  may  discharge  through  the  external  meatus,  gaining 
access  to  the  canal  through  fissures  in  the  cartilage  called  the  fissiires  of  Santorini. 
The  cartilaginous  portion  of  the  meatus  contains  sweat-glands,  sebaceous  glands,  and 
hair-follicles.  There  are  only  a  few  glands  in  the  upper  posterior  portion  of  the  bony 
meatus.  On  account  of  the  location  of  the  glands  in  the  e.xternal  portion  of  the  canal, 
accumulations  of  wax,  and  abscesses,  which  result  from  infection  of  the  glands,  occur 
nearer  to  the  surface  than  to  the  drum  membrane.  It  is  only  when  the  canal  begins  to 
fill  up  that  the  wa.x  pushes  its  way  to  the  membrane.  When  furuncles  occur,  the  lining 
membrane  swells  and  by  closing  the  canal  prevents  a  view  of  the  drum  being  ob- 
tained. Incising  of  furuncles  of  the  auditory  meatus  is  sometimes  required.  The 
site  of  the  inflamed  spot  having  been  located,  an  incision  can  be  made  where 
indicated.  If  care  is  exercised,  one  is  not  likely  to  injure  the  drum  membrane, 
because  the  abscess  starts  in  one  of  the  sebaceous  glands,  which  are  located  in  the 
external  half  of  the  meatus.  The  membrane  lies  2. 5  cm.  from  the  surface,  and  the 
point  of  the  knife  should  not  be  carried  so  deeply  as  that  for  fear  of  wounding  it; 
there  is  no  necessity  of  going  so  far  inward. 


THE    EAR.  87 

The  meatus  is  supplied  by  the  auriculotemporal  branch  of  the  fifth  and  the 
armcular  branch  of  the  pneumogastric  nerve.  Irritation  of  the  latter  nerve  is  said 
to  be  the  cause  of  feeling  it  in  the  throat  when  anything  is  put  in  the  ear. 

Membrana  Tympani. — The  membrana  tympani  is  inclined  downward  and 
inward  at  an  angle  of  about  140°  to  the  upper  wall  (Troltsch)  and  27°  to  the  lower 
wall  (Bezold)  of  the  meatus  ;  it  does  not  lie  directly  transverse,  therefore  in  intro- 
ducing instruments  into  the  ear  the  upper  posterior  part  will  be  first  encountered. 
The  membrane  is  located  2.5  cm.  (i  in.)  from  the  surface;  this  is  to  be  borne  in 
mind  in  puncturing  the  membrane  or  other  operations.  The  membrane  has  three 
coats:  an  outer,  continuous  with  the  skin  of  the  meatus;  a  fibrous  or  middle  layer; 
and  an  internal  or  mucous  layer,  continuous  with  the  lining  of  the  tympanic  cavity. 
The  membrana  tympani  at  birth  is  fastened  at  its  circumference  to  the  tympanic 
bone,  which  unites  with  the  other  portions  of  the  temporal  bone  soon  after  birth. 
This  ring  of  bone  is  incomplete  at  its  upper  portion  for  a  distance  equaling  one-eighth 
of  its  circumference.  This  is  called  the  notch  of  Rivhius.  The  fibrous  layer  does 
not  extend  across  this  notch,  which  is  closed  by  the  mucous  membrane  on  the  inside 
and  by  the  skin  layer  of  the  membrane  on  its  outer  side.      The  part  closing  the  notch 

.Membrana  flaccida 


Short  process  of  malleus  • 


Long  handle  of  i 


Fig.  102. — Outer  surface  of  the  tympanic  membrane  of  the  left  ear. 

is  called  ShrapnelV s  membrane  or  membrana  flaccida.  As  it  possesses  no  fibrous 
layer  it  is  weaker  than  the  membrane  elsewhere  and  consequently  is  a  favorite  spot 
for  pus  to  perforate  in  order  to  find  e.xit  from  the  middle  ear. 

In  examining  the  membrane  by  means  of  light  thrown  into  the  meatus  through 
a  speculum  by  the  head  mirror,  one  sees  extending  downward  from  its  centre  a  small 
cone  of  light;  any  depression  or  bulging  of  the  membrane  will  cause  this  cone  of 
light  to  be  altered  in  its  position,  or  even  cause  it  to  disappear  entirely.  From  the 
centre  of  the  membrane  upward  extends  a  line  which  indicates  the  attachment  of  the 
long  handle  of  the  malleus,  one  of  the  bones  of  the  middle  ear.  Stretching  across 
the  upper  portion  is  the  membrane  of  Shrapnell  or  membrana  flaccida,  so  called  on 
account  of  its  not  being  so  tense  as  the  remaining  portion.  It  is  better  supplied 
with  blood-vessels  than  the  other  portion. 

The  membrana  tympani  is  of  surgical  interest  on  account  of  its  being  often  dis- 
tended or  perforated.  A  purulent  discharge  from  the  ear  usually  indicates  disease 
of  the  middle  ear  or  tympanum.  If  pus  is  coming  from  a  furuncle  of  the  meatus,  the 
latter  will  be  swollen  and  its  source  can  readily  be  recognized.  If  it  comes  from 
outside  of  the  meatus,  as  in  cases  of  suppuration  of  the  parotid  gland,  it  will  be  recog- 
nized by  an  examination  of  the  gland.  There  is  no  other  source  of  pus  but  the 
middle  ear  and  for  it  to  gain  exit  it  must  perforate  the  membrane;  this  perforation 
can  usually  be  seen  with  the  speculum  and  head  mirror,  as  can  also  bulging. 

In  inflammation  of  the  middle  ear  the  effused  serum  or  pus  bulges  the  mem- 
brane outward.     When  this  condition  is  accompanied,  as  it  often  is,  by  intense  pain, 


88 


APPLIED    ANATOMY. 


pa}-acenfesis  or  puncture  is  resorted  to.  The  preferable  spot  is  the  posterior  lower 
quadrant.  Paracentesis  of  the  membrane  should  be  done  by  beginning  the  incision  a 
little  above  and  behind  the  centre  of  the  tympanic  membrane,  which  slopes  downward 
and  forA\-ard  at  an  angle  of  140°  to  the  upper  wall,  and  cutting  downward  to  its 
lower  edge.  One  must  avoid  the  long  handle  of  the  malleus,  which  extends  directly 
upward  from  the  centre  of  the  membrane.  In  the  upper  posterior  part  are  the  incus 
and  stapes,  therefore  this  portion  should  be  avoided;  and  running  across  the  upper 
edge  beneath  the  mucous  membrane  is  the  chorda  tympani  nerve.  Division  of  this 
nerve  is  said  to  be  a  matter  of  not  much  account.  Incision  through  the  anterior  part 
is  not  considered  suitable  for  drainage. 

Perforations  frequentl)-  occur  through  Shrapnell's  membrane  on  account  of  its 
not  having  any  fibrous  layer;  thus  the  pus  does  not  go  through  the  tympanic  mem'- 
brane  proper.  If  perforation  with  a  purulent  discharge  has  existed  for  a  long  time 
granulations  come  through  the  opening,  forming  an  aural  polyp.  To  remove  these 
a  snare  is  used  or  caustic  is  applied. 

The  Tympanum  or  Middle  Ear. — The  tympanic  cavity  is  flat  and  narrow 
and  is  situated  directly  behind  and  also  above  the  membrane.  It  has  a  floor  and 
roof,  and  external  and  internal  walls.  It  is  divided  into  the  portion  behind  the  mem- 
brane and  the  portion  abo\'e  the  membrane  called  the  attic.  The  floor  is  narrower 
than  the  roof  and  is  formed  by  the  tympanic  plate.,  which  separates  it  from  the  jugular 


Aditus 
Facial  i 

Oval  window 
Canal  for  tensor 
t>mpani  muscle 


Carotid  canal 


Eustachian  tube 


-Right  temporal  bone : 


-The  outer  snriace  has  been  cut  away,  exposing  the  tympanic  i 
the  mastoid  antrum.  Eustachian  tube,  etc. 


fossa  containing  the  commencement  of  the  internal  jugular  vein.  The  bone  forming 
the  floor  is  more  difficult  for  pus  to  perforate  than  is  that  of  the  roof,  so  that  exten- 
sion of  middle-ear  disease  is  less  frequent  through  it.  The  roof  is  comparatively 
thin  and  formed  of  cancellous  tissue  with  a  thin  and  weak  outside  compact  layer; 
therefore  it  is  a  somewhat  common  site  for  pus  to  perforate  and  thereby  obtain 
access  to  the  middle  fossa  of  the  skull.  The  distance  from  the  floor  to  the  roof  is 
approximately  15  mm.  {\  in.);  half  is  behind  the  membrane  and  the  rest  forms 
the  attic  above. 

The  exteinial  wall  is  formed  below  by  the  tympanic  membrane  and  above  by 
the  bone.  As  the  membrane  is  the  weakest  portion  of  the  walls,  collections  of  pus 
in  the  middle  ear  most  often  find  a  vent  through  it.  Immediately  behind  the  mem- 
brane are  the  lower  portions  of  the  ossicles,  and  above  is  the  chorda  tvmpani  nerve. 

The  internal  wall  is  formed  of  bone  and  is  from  2  to  4  mm.  (yV  to  \  of  an 
inch)  behind  the  membrane.  It  is  so  close  that  in  doing  the  operation  of  para- 
centesis care  must  be  taken  not  to  thrust  the  knife  too  deeply.  In  it  are  the  oval 
and  round  windows  (Fig.   103). 

There  is  no  well-defined  anterior  or  posterior  wall.  The  anterior  portion  of  the 
cavity  is  continued  forward  into  the  Eustachian  tube;  the  canal  for  the  tensor 
tvmpani  muscle  is  immediateh'  abo\'e  it.  Posteriorly  the  cavity  of  the  attic  is  con- 
tinuous through  the  aditus  with  the  mastoid  antrum  and  the  cells  beyond.      Posterior 


THE    EAR.  89 

to  the  opening  of  the  Eustachian  tube  is  an  elevation  on  the  internal  wall  called  the 
promo7ito7y ,  formed  by  one  of  the  semicircular  canals.  Above  the  promontory  is  the 
fenestra  ovalis,  which  lodges  the  stapes  bone  and  communicates  with  the  vestibule. 
Below  and  behind  is  the  fenestra  rotunda,  closed  by  a  membrane  separating  the 
cochlea  from  the  middle  ear.  Above  the  fenestra  ovalis  is  a  ridge  of  bone  marking 
the  aqueduct  of  Fal/opius,  in  which  runs  the  facial  nerve. 

The  Eustachian  tube  passes  from  the  anterior  portion  of  the  tympanic 
cavity  downward,  forward,  and  inward  to  the  upper  posterior  portion  of  the  pharyn.x 
about  level  with  the  floor  of  the  nose.  It  is  about  3.5  cm.  (approximately  i  J4  in.) 
in  length.  The  outer  third,  near  the  ear,  is  bony  and  the  inner  two-thirds  are 
cartilaginous.  The  point  of  junction  of  the  bony  and  cartilaginous  portions  is  the 
narrowest  portion  of  the  tube  and  is  called  the  isthmus.  The  tube  is  usually  closed, 
but  opens  in  swallowing,  yawning,  etc.,  thus  admitting  air  to  the  tympanic  cavity 
and  mastoid  cells.  Catarrhal  affections  of  the  throat  readily  travel  up  the  tube  and 
set  up  an  inflammation  of  the  middle  ear.  Swelling  of  the  lining  of  the  tube  follows 
and  air  no  longer  passes  to  the  ear.  To  open  the  tube  two  methods  are  employed — 
that  of  Valsalva,  and  that  of  Politzer.  The  former  consists  in  holding  the  nostrils  and 
mouth  shut  and  attempting  to  blow,  when  the  action  of  the  throat  and  palate  muscles 
opens  the  tube  and  allows  the  air  to  enter.      In  the  method  of  Politzer,  the  patient  is 


Tegmen  tympani 

Chorda  tympan 

Long  handle  of  i 


rensor  tympani  muscle 


Eustachian  tube 


Fig.  104. — View  of  the  tympanii 


cles  of  the  left  < 


given  a  sip  of  water  which  he  swallows  on  command.  The  nozzle  of  a  rubber  air-bag  is 
placed  in  one  nostril  and  the  other  held  shut.  As  the  patient  swallows,  the  air-bag  is 
compressed  and  the  air  enters  the  Eustachian  tube.  Sometimes  this  method  is  varied 
by  asking  the  patient  to  say  '  'hock, ' '  thus  causing  the  tube  to  open,  when  the  air-bag  is 
compressed.  The  calibre  of  the  tube  is  sometimes  so  small  that  probes  are  passed 
up  it  to  dilate  it.  Care  is  necessary  to  avoid  introducing  the  probe  too  far  or  it  will 
injure  the  ossicles  of  the  ear.  Pus  will  sometimes  discharge  through  the  tube.  I 
have  seen  pus  coming  from  the  middle  ear  pass  down  the  tube  into  the  inferior 
meatus  and  be  blown  out  the  anterior  nares. 

Lying  in  a  separate  canal  immediately  above  and  parallel  with  the  Eustachian 
tube  is  the  canal  for  the  tensor  tympani  muscle. 

The  attic  is  directly  above  the  tympanic  cavity  and  contains  the  greater  part  of 
the  ossicles.  Between  the  two  along  the  inner  wall  runs  a  ridge  of  bone  within  which 
is  the  aquEeductus  Fallopii,  containing  the  facial  nerve.  The  roof  of  the  attic  is  called 
the  tegmen.  It  is  a  thin  shell  of  bone,  varying  in  thickness,  and  separates  the  cavity 
of  the  ear  from  the  middle  cerebral  fossa  above.  Pus  frequently  eats  its  way  through 
at  this  point  and  forms  a  subdural  abscess,  which  by  working  its  way  backward 
involves  the  lateral  (transverse)  sinus,  causing  thrombosis  and  general  septic  infection. 


90 


APPLIED    ANATOMY. 


The  antrum  is  a  little  larger  than  the  attic.  The  two  cavities  are  continuous 
through  the  aditus.  The  roof  of  the  antrum  is  level  with  the  roof  of  the  attic  and  its 
floor  is  about  level  with  the  top  of  the  membrane.  It  is  thus  seen  to  be  directly 
above  and  posterior  to  it. 

Mastoid  Cells.  — The  mastoid  cells  are  continuous  with  the  antrum  and 
permeate  the  mastoid  process  down  to  its  tip.  The  cells  come  so  close  to  the  surface 
that  suppuration  within  them  often  bursts  through  and  discharges  behind  the  ear. 
The  upper,  inner,  and  lower  portions  of  the  bone  are  also  sometimes  perforated,  which 
will  be  referred  to  later. 

Middle-ear  Disease. — Suppuration  from  middle-ear  disease  is  caused  by  an 
infective  inflammation  travelling  up  the  Eustachian  tube  from  the  pharynx  and  nasal 
cavities.  It  may  pass  to  the  attic  above  and  thence  to  the  mastoid  antrum  and 
mastoid  cells.  Pus  usually  finds  an  exit  by  perforating  the  tympanic  membrane  and 
discharging  through  the  external  auditory  meatus.  As  already  stated,  it  may  pass 
down  the  Eustachian  tube  to  be  blown  out  of  the  anterior  nares.  It  has  been  known 
to  pass  down  the  canal  for  the  tensor  tympani  muscle,  and  form  a  retropharyngeal 
abscess.  As  the  pus  reaches  the  pharynx  behind  the  prevertebral  fascia,  it  may 
e.xtend  laterally  and  appear  externally  behind  the  sternomastoid  muscle.  Having 
thus  reached  the  base  of  the  skull,  the  infection  may  involve  the  meninges  and  brain 
through  the  crevices  in  the  bone.      It  is  rare  for  it  to  perforate  the  bone  below  and 


Fig.   105. — Tenotuiiu-  oE  the  tensor  tympani  tendon 
and  separation  of  the  incus  from  the  stapes. 

Modified  from  Georges  Laurens 


anteriorly,  and  thus  implicate  the  jugular  vein  and  internal  carotid  artery.  It  may 
eat  into  the  posterior  wall  and  involve  the  facial  nerve,  which  is  covered  hy  only  a 
thin  shell  of  bone,  and  produce  facial  paralysis,  attack  the  internal  ear  through  the 
fenestra  ovalis  and  rotunda  and  pass  through  the  internal  meatus  to  the  brain.  If  it 
e.xtends  upward  and  involves  the  attic  and  antrum,  it  may  perforate  the  roof,  or 
tegmen,  and  form  a  subdural  abscess  in  the  back  part  of  the  middle  cerebral  fossa, 
whence  it  travels  a  distance  of  about  a  centimetre  to  the  lateral  sinus,  causing  a 
thrombus  to  form,  or  it  may  produce  an  abscess  of  the  temporosphenoidal  lobe  of 
the  brain.  The  antrum  and  mastoid  cells  being  continuous,  the  posterior  and  inner 
walls  may  be  perforated,  the  pus  thereby  reaching  the  posterior  cerebral  fossa, 
again  involving  the  lateral  sinus,  or  producing  a  cerebellar  abscess.  If  it  perforates 
the  mastoid  process  on  its  inner  wall  at  the  groove  for  the  digastric  muscle,  the  pus 
gains  access  to  the  back  of  the  neck,  forming  what  is  known  as  Bczold'  s  abscess. 

Operations  on  the  Middle  Ear. — The  operations  on  the  middle  ear,  besides 
those  involving  the  membrane,  are  done  either  for  the  removal  of  the  remains  of  the 
membrane  and  ossicles,  or  else  to  clear  out  the  antrum  and  mastoid  cells  and  even, 
if  necessary,  examine  the  lateral  sinus  and  jugular  vein  and  explore  the  brain.  They 
are  done  for  suppurative  affections,  which  may  be  either  chronic,  producing  local 
symptoms,  or  acute,  producing  in  addition  constitutional  disturbances  and  even 
general  infection.      Caries  of  the  bones  is  a  prominent  condition  in  suppurative  cases 


THE    EAR. 


91 


of  long  standing,  and  the  character  of  the  operation  is  dependent  on  the  extent  to 
which  the  disease  has  progressed. 

In  removal  of  the  ossicles,  the  tympanic  membrane  is  first  separated  around  its 
edges.  Then  the  tendon  of  the  tensor  tympani  muscle  is  cut,  and  the  incus  disarticu- 
lated from  the  stapes.  The  latter  is  done  by  cutting  with  a  bent  knife  across  the 
axis  of  the  stapes  and  not  of  the  incus  (see  Fig.  105J.  The  malleus  is  seized  and 
drawn  first  down  and  then  out,  bringing  the  membrane  with  it,  and  afterwards  the 
incus,  which  is  detached  by  Ludwig's  hook  (see  Fig.  106),  is  removed,  and,  if 
desired,  the  stapes.  Granulations  and  pus  are  removed  by  the  snare,  forceps  or 
curette.  Care  is  to  be  taken  to  avoid,  if  possible,  scraping-  away  the  thin  shell  of 
bone  on  the  internal  wall  that  covers  the  facial  nerve.  Any  twitching  of  the 
muscles  of  the  face  indicates  that  the  nerve  is  being  irritated.  The  chorda 
tympani  nerve,  which  passes  on  the  inner  side  of  the  handle  of  the  malleus  and  lies 
beneath  the  mucous  membrane,  is  of  necessity  removed.  No  important  symptoms 
follow  its  remo\'al. 

Operations  on  the  Antrum  and  Mastoid  Cells. — In  order  to  understand 
these  operations,  one  must  recall  that  the  supraineatal  crest  is  the  ridge  of  bone  forming 
the  upper  edge  of  the  bony  meatus,  and  a  continuation  backward  of  the  posterior  root 


Suprameatal  sp 


Posterior  root  of  zygoma 


Fig.  107. — Landmarks  for  operating  to  enter  the  mastoid  antrum. 

of  the  zygoma.  The  upper  and  posterior  edge  of  the  meatus  is  formed  by  a  thin,  small 
shell  or  edge  of  bone  running  from  the  suprameatal  crest  downward  and  backward 
to  the  posterior  wall;  this  is  the  sjiprameatal  spine.  Behind  the  suprameatal  spine 
and  between  it  and  the  posterior  portion  of  the  suprameatal  crest  is  a  depression, 
the  suprameatal  fossa.  This  suprameatal  fossa  is  triangular  in  shape.  The  crest 
forms  the  upper  side,  the  spine  its  anterior  side,  and  the  ridge  of  bone,  running  from 
the  posterior  portion  of  the  crest  to  the  lower  portion  of  the  spine,  forms  the  posterior 
side.  These  three  lines  form  the  suprameatal  triangle  of  Macewen.  It  is  through 
this  triangle  that  the  antrum  may  be  reached.  The  operation  may  be  restricted  to  the 
antrum  and  tympanic  cavity,  or  may  include  the  whole  or  part  of  the  mastoid  cells, 
constituting  the  operation  known  as  tympanomastoid  exenteration. 

To  reach  the  antrum  a  semicircular  cut  is  made  a  centimetre  back  of  the  ear 
and  the  ear  and  membranous  canal  loosened  and  pushed  forward.  With  a  gouge 
chips  of  bone  are  removed  from  the  suprameatal  spine  backward  and  from  the  crest 
downward  as  far  as  desired.  This  will  extend  considerably  beyond  the  line  marking 
the  posterior  boundary  of  Macewen' s  triangle.  The  outer  table  of  bone  being 
removed,  the  cells  are  broken  through  parallel  to  the  meatus  and  slightly  upward, 


92 


APPLIED    AXATOMY. 


for  the  lower  level  of  the  antrum  corresponds  to  the  upper  edge  of  the  meatus. 
It  is  hardly  safe  to  penetrate  deeper  than  1.5  cm.  (fin.)  from  the  meatal  spine 
inward,  for  fear  of  wounding  the  facial  ner\"e.  The  mastoid  antrum  lies  not  only 
above  and  posterior  to  the  membrane  and  t}-mpanic  ca^'ity,  but  extends  outward 
along  the   posterior  and   upper   portion   of  the  canal,  and  the   facial  ner\'e  can  be 

Mastoid  antrum 

External  auditory  meatus 


Fig.  ioS. — The  mastoid  antrum  exposed  by  chiselling  through  the  suprameatal  triangle.    The  mastoid  cells  exposed 
by  chiselling  off  the  surface  of  the  mastoid  process. 

wounded  only  by  passing  across  the  antrum  and  attacking  the  bony  covering  of  the 
Fallopian  canal  below  and  anteriorly. 

In  doing  a  tympanomastoid  exenteration,  a  more  extensive  procedure  is 
performed.  It  consists  in  cleaning  out  the  various  communicating  ca\ities  and 
throwing  them  together,  thus  making  their  interior  more  accessible.      The  antrum  is 

reached  in  one  of  two  ways :  either 
posteriorly,  or  anteriorly  through 
the  meatus.  The  posterior  opera- 
tion, or  that  of  Schwartze,  Zaufal, 
and  others,  consists  in  removing 
the  membranous  lining  of  the  bony 
meatus  on  its  upper  and  posterior 
portions  down  to  the  tympanic 
membrane.  The  antrum  is  then 
entered  as  already  described;  the 
posterior  bony  wall  of  the  meatus 
is  chiselled  away,  gi\"ing  access  to 
the  tympanum;  the  ridge  of  bone 
separating  the  roof  of  the  bony 
meatus  from  the  attic  or  epitym- 
panum  is  chiselled  a\\ay  (see  Fig. 
109),  and  the  membrane  and  os- 
sicles removed.  This  gives  access 
to  the  tympanic  ca\'ity,  epitym- 
panum,  and  antrum.  As  much  of 
the  mastoid  cells  as  necessary  is 
exposed  by  chiselling  a\\-ay  their  external  cox'ering  of  bone  even  down  to  the  tip  of 
the  mastoid  process. 

If  the  anterior  operation  of  Stacke  is  performed,  the  membranous  lining  of  the 
bony  meatus  is  to  be  loosened  and  divided  as  close  to  the  membrane  as  possible  and 
drawn  forward  with  the  cartilaginous  meatus.  The  dmm  membrane  and  as  much  of 
the  ossicles  as  possible  are  then  to  be  removed,  and  with  a  chisel  or  bent  gouge  the 


Fig.  loQ. — Chiselling  away  the  spur  of  bone  between  the  roof  of  the 
external  auditory  meatus  and  attic  or  epitympanum. 


THE    EAR. 


93 


angle,  or  ridge  of  bone  between  the  upper  side  of  the  bony  meatus  and  epitympanum, 
or  attic,  cut  away.  The  antrum  is  now  entered  by  chiselling  away  the  upper  posterior 
wall  and  the  chiselling  away  of  bone  continued  until  the  mastoid  cells  have  been  suffi- 
ciently exposed.     The  final  result  of  these  two  methods  is  the  same.     The  external 


Suprameatal  spine 


Anterior  root  of 


Posterior  root 
of  zygoma 


Mastoid  process 


External  auditory  meatus 
:  transverse  sini 


meatus,  tympanum,  epitympanum,  antrum,  and  mastoid  cells  are  all  thrown  into  one 
large  cavity.  Wounding  of  the  facial  nerve  is  to  be  avoided  by  first  learning  its  course 
and  then  by  sponging  away  the  blood  and  cutting  only  the  structures  which  are 
clearly  visible.  Tracing  the  facial  nerve  backward,  it  is  seen  (Fig.  103)  entering 
the  stylomastoid  foramen, 
passing  upward  posterior 
to  the  tympanic  cavity, 
and  crossing  at  about  its 
upper  edge  to  pass  above 
the  oval  window.  Viewed 
in  Fig.  101,  it  is  seen  that 
the  Fallopian  canal  lies  a 
trifle  nearer  to  the  external 
surface  than  does  the  tym- 
panic membrane,  so  that 
in  making  the  opening  into 
the  antrum  or  in  connect- 
ing the  mastoid  cells  below 
the  antrum  with  the  tym- 
panic cavity,  care  should 
be  taken  to  keep  a  little 
anterior  or  superficial  to 
the  membrane. 

Relations  of  the 
Brain  and  Lateral  Si- 
nus.—  Inoperatingon  the 
skull  for  middle-ear  dis- 
ease, it  is  desirable  to  know 
how  to  reach  and  how  to  avoid  the  brain  and  lateral  sinus.  The  lower  level  of  the 
brain  in  the  region  of  the  ear  corresponds  to  a  prolongation  directly  backward  in  a 
straight  line  of  the  posterior  root  of  the  zygoma.  If  one  keeps  below  this  line,  he  is 
not  likely  to  open  the  brain  case.     If  it  is  desired  to  explore  the  under  surface  of  the 


Jugular  foramen 


94  APPLIED    ANATOMY. 

brain  or  dura  directly  over  the  middle-ear  cavity,  then  one  trephines  above  this  line 
or  suprameatal  crest,  the  lower  edge  of  the  trephine  opening  being  .5  cm.  above  it. 
This  will  lead  to  the  middle  fossa  of  the  skull,  occupied  by  the  temporosphenoidal 
lobe.  The  sharp  upper  and  posterior  edge  of  the  petrous  portion  of  the  temporal 
bone  gives  attachment  to  the  tentorium  and  separates  the  middle  cerebral  fossa  in 
front  from  the  posterior  fossa,  containing  the  cerebellum,  behind.  The  point  at  which 
this  ridge  and  tentorium  reach  the  side  of  the  skull  is  indicated  by  the  point  of  cross- 
ing of  a  line  drawn  up  from  the  tip  of  the  mastoid  process,  midway  between  its  anterior 
and  posterior  borders,  and  the  line  of  the  posterior  root  of  the  z3'goma.  The  course 
of  the  lateral  sinus  is  indicated  by  a  cur\'ed  line  from  above  and  to  the  right  (about 
.5  to  I  cm.)  of  the  external  occipital  protuberance  to  the  upper  posterior  portion  of 
the  mastoid  process  and  thence  to  its  tip.  The  anterior  edge  of  the  lateral  sinus 
reaches  as  far  forward  as  a  line  drawn  from  the  tip  of  the  mastoid  upward,  midway 
between  its  anterior  and  posterior  borders.  The  point  at  which  it  turns  is  where  this 
mastoid  line  intersects  the  line  of  the  zygoma.  Its  upper  edge  rises  above  this  line 
appro.ximately  i  cm.  The  sinus  is  I  cm.  in  width.  The  distance  of  the  sinus  from 
the  surface  varies  from  .5  cm. ,  or  even  less,  at  the  top  of  the  mastoid  process  to  1.5 
cm.  at  its  tip.  So  uncertain  is  this  that  the  only  safe  way  to  expose  the  sinus  is  to 
cut  the  bone  oil  with  a  mallet  and  gouge  in  thin  chips  parallel  to  the  surface.  The 
use  of  a  trephine  or  other  boring  instrument  is  not  to  be  advised.  If  the  infection 
of  the  lateral  sinus  has  extended  to  the  jugular  vein  this  latter  must  be  reached  by 
means  of  a  separate  incision  in  the  neck. 

THE    NOSE. 

Externally  the  nose  forms  a  prominent  projection  on  the  face,  hence  it  is  fre- 
quently injured  and  its  construction  should  be  studied  in  relation  to  those  injuries. 
It  forms  a  conspicuous  portion  of  the  features,  hence  deformities  or  disfigurements  of 
it  are  very  distressing,  so  that  plastic  operations  are  done  for  their  relief.  Internally, 
the  nasal  cavities  are  concerned  in  the  sense  of  smell  and  form  the  passage-way  to 
and  from  the  lungs  and  the  various  accessory  cavities  for  the  air  in  respiration.  It 
likewise  serves  as  a  receptacle  for  the  tears  as  they  come  down  the  lachrymonasal 
duct.  Interference  with  the  flow  of  air  by  obstruction  of  the  nasal  chambers  may 
cause  affections  of  the  pharyn.x,  laryn.x,  lungs,  ears,  or  accessory  sinuses — ethmoid, 
sphenoid,  maxillary,  and  frontal.  Catarrhal  troubles  may  start  in  the  nose  and  invade 
any  of  these  parts.  They  ma)''  even  e.xtend  up  the  Eustachian  tube  and  cause  deaf- 
ness; or  up  the  lachrymonasal  duct  and  cause  trouble  with  the  lachrymal  canal  or 
conjunctiva.  A  knowledge  of  the  nose  is  essential  to  all  those  who  wish  to  devote 
themselves  especially  to  affections  of  the  eye,  ear,  and  throat,  because  the  origin  of 
the  affections  of  these  organs  may  be  in  the  nasal  chambers  instead  of  the  organ  in 
which  they  are  most  manifest. 

The  skin  over  the  root  of  the  nose  is  thin  and  lax.  It  is  well  supplied  with 
blood  by  the  frontal  and  nasal  branches  of  the  ophthalmic,  and  the  angular  branch 
of  the  facial  arteries.  In  reconstructing  a  nose  bv  means  of  a  flap  taken  from  the 
forehead,  it  is  these  branches  that  nourish  it.  The  laxity  of  the  skin  allows  the 
pedicle  to  be  twisted  around  without  interfering  with  the  circulation. 

The  skin  over  the  tip  and  alae  is  thick  and  adherent  to  the  cartilages.  It  pos- 
sesses a  comparatively  scanty  blood  supply,  hence  its  liability  to  suft'er  from  cold,  and 
is  a  favorite  site  for  ulcerations,  as  lupus,  superficial  epithelioma  (rodent  ulcer),  etc. 
Sebaceous  and  sweat  glands  are  abundant,  and  stiff  hairs  guard  the  inside  of  the  nos- 
trils. These  latter  are  not  seldom  the  seat  of  small  furuncles  or  boils,  which  are 
extremely  painful.  This  is  due  to  the  tension  caused  by  the  congestion  and  swelling, 
which  is  restricted  by  the  tissues  being  so  firmly  bound  to  the  cartilages  beneath. 

Nerves. — In  addition  to  the  olfactory  nerve,  the  nose  is  supplied  by  the  nasal, 
infratrochlear,  and  infra-orbital  branches  of  the  fifth  ner\'e,  hence  the  eyes  water 
when  the  nose  is  injured.  In  certain  cases  of  neuralgia  affecting  the  ophthalmic 
division  of  the  fifth  nerve,  pain  is  felt  along  the  side  of  the  nose.  As  the  nasal 
nerve  enters  the  skull  from  the  orbit  through  the  anterior  ethmoidal  foramen,  it  may 
be  involved  in  disease  of  the  ethmoidal  sinuses. 


THE    NOSE. 


95 


Small  alar 
cartilagL' 


Nasal 
aperture 


Cartilage 
at  tip 


Septal 
cartilage 


The  nose  proper  consists  of  a  bony  and  a  cartilaginous  portion.  The  bonyportio7i 
is  formed  by  the  two  nasal  bones  articulating  with  the  frontal  bone  above,  with  each 
other  in  the  median  line,  and  with  the  nasal  process  of  the  superior  maxilla  on  the 
side.  They  are  supported  on  the  inside  by  the  upper  anterior  portion  of  the 
perpendicular  plate  of  the  ethmoid. 
This  articulation  does  not  extend  "^ 

the  whole  length  of  the  nasal  bones 
to  their  tip,  but  only  about  half 
their  length. 

The  cartilaginous  portion 
consists  of  four  lateral  cartilages, 
two  on  each  side,  upper  and  lower, 
and  the  triangular  cartilage,  or  car- 
tilaginous septum  on  the  inside. 

The  external  shape  of  the  nose  ^°^^^!,'f',^''^3 
viewed  in  profile  is  composed  of 
three  portions:  an  upper  of  bone, 
a  middle  of  cartilage — the  upper 
lateral  cartilages — and  a  lower,  or 
tip,  formed  by  the  lower  lateral  car- 
tilages. The  bridge  of  the  nose  is 
formed  by  bone;  it  slopes  down- 
ward and  forward  and  where  it  joins 
the  upper  lateral  cartilage  the  line 
changes  and  slopes  more  downward,  until  the  tip  is  reached,  here  the  lower  lateral 
cartilages  bulge  forward,  forming  a  rounded  and  more  or  less  projecting  tip. 

Injuries  to  the  Nose. — The  bones  and  cartilages  may  be  fractured  or 
dislocated.  This  may  involve  either  the  outside  structures  or  those  forming  the 
septum,  and  often  both.      The  displacement  depends  on  the  character  and  direction 


Fig.  112.— Eon> 


nd  cartilaginous  frai 
aspect      (Piersol  ) 


Fig.  113. — Fracture  of  the  nose  with  deflec 


al  bone  laterally. 


of  the  injury.  It  is  either  a  displacement  to  one  side,  or  the  nose  is  crushed, 
producing  a  flattening  of  the  bridge.  If  the  displacement  is  lateral,  whether  by  a 
dislocation  or  fracture,  there  is  liable  to  be  a  deviation  of  the  septum,  because  the 
bony  and  cartilaginous  septum  is  connected  with  the  bones  and  is  apt  to  be  carried 
with  them  to  the  side.  If  the  displacement  is  inward,  not  only  are  the  nasal  bones 
depressed,  but  the  septum  beneath  may  be  either  bent  or  fractured.  The  pushing 
of  the  septum  toward  the  floor  causes  it  to  buckle  and  bend  or  even  break  at  the 


96  APPLIED    ANATOMY. 

iunction  of  the  triangular  cartilage  with  the  perpendicular  plate  of  the  ethmoid  and 
the  vomer.  In  treating  these  fractures,  the  most  efficient  method  is  to  grasp  the 
septum  with  the  flat  blades  of  an  Adams  forceps  (after  cocainization)  and  lift 
the  bones  up  or  to  one  side  as  needed.  In  cases  where  it  is  not  desired  to  use 
the  forceps,  the  writer  grasps  the  nose  with  a  wet  towel,  makes  traction  to  loosen 
the  fragments,  and  then  pushes  them  over  into  place.  The  triangular  cartilage  is 
frequently  injured;  with  the  displacement  or  loosening  of  the  upper  lateral  cartilages 
a  great  amount  of  displacement  may  be  caused,  so  that  the  nose  instead  of  forming  a 
straight  line  is  bent  to  one  side  from  the  ends  of  the  bones  down  to  the  tip.  Injuries 
to  the  septum  in  childhood  are  probably  the  cause  of  a  large  number  of  the  cases  of 
deviation  of  the  septum,  spurs,  etc.,  seen  later  in  life. 

In  fractures  the  mucous  membrane  is  often  torn,  thus  allowing  air  to  enter  the 
tissues  at  the  site  of  fracture,  producing  emphysema.  If  such  a  patient  blows  the 
nose  violently,  the  air  may  be  forced  under  the  skin  of  the  face,  around  the  eyes  and 
up  the  forehead. 

Anterior  Nares. — The  nostrils  or  anterior  nares  in  the  white  race  are  an 
elongated  oval  in  shape  and  run  in  an  anteroposterior  direction,  being  separated  from 
each  other  by  the  columna.      They  lie  in  a  direction  parallel  with  the  floor  of  the  nose, 


Fig.  114  — Fracture  of  the  nose  showing  depression  of  the  nasal  bone. 

SO  that  to  examine  the  nasal  fossae  with  a  speculum  the  instrument  is  first  introduced 
from  below,  then  tilting  the  tip  of  the  nose  upward,  the  speculum  is  directed  back- 
ward. To  see  the  floor  of  the  nose,  it  is  necessary  to  raise  the  outer  end  of  the 
speculum  still  higher,  because  the  floor  is  below  the  bony  edge.  From  the  outer 
edge  of  the  nostril  the  nasal  cavities  go  upward  and  backward  for  a  distance  of  .  5  to 
I  cm.  This  part,  called  the  vestibule,  is  covered  by  skin,  not  mucous  membrane. 
It  bears  stiff  hairs — vibrissae.  Inflammation  of  these  hair-follicles  and  associated 
glands  produces  e.xceedingly  painful  pustules .  It  is  here  likewise  that  dried  mucus 
collects  and  forms  scabs,  which  stick  to  the  hairs  and  are  hard  to  remove.  The 
attempt  to  remove  them  probably  is  the  cause  of  infection  and  inflammation  around 
the  roots  of  the  hairs.  The  vestibule  leads  to  the  ridge  of  bone  or  crest,  which  is 
directly  posterior  to  the  side  of  the  nasal  spine.  This  ridge  of  bone  is  on  a  higher 
level  than  the  floor  of  the  nose,  and  in  order  to  view  the  latter  the  nostrils  must  be 
raised,  by  means  of  the  speculum,  above  it  (Fig.  115). 

View  from  the  Aiitei'ior  Nares. — In  looking  into  the  nose  from  in  front,  if  the 
speculum  is  directed  downward,  the  floor  of  the  nose  and  the  inferior  meatus  can 
be  seen.      On  the  inner  side  is  the  septum,   on  the  outer  the  anterior  end  of  the 


THE    NOSE. 


97 


of  the  interior  of  the 


inferior  turbinated  bone.  Still  higher  is  the  middle  meatus  and  the  anterior  end  of  the 
middle  turbinated  bone.  The  superior  turbinated  bone  is  not  visible  from  the  front, 
being  in  the  upper  posterior  corner  and  hidden  from  sight  by  the  middle  turbinated. 
Sometimes  in  the  upper  portion  of 
the  nose,  beneath  the  outer  surface 
of  the  anterior  extremit)-  of  the  mid- 
dle turbinated  bone,  is  seen  a  small 
cleft,  the  hiatus  semilunaris,  leading- 
through  the  infundibulum  into  the 
frontal  sinus.  If  the  inferior  turbi- 
nated has  been  shrunk  with  cocaine, 
and  if  the  inferior  meatus  is  roomy, 
one  can  see  the  posterior  wall  of  the  'n 
pharynx.  This  can  be  seen  moving 
if  the  patient  swallows,  pronounces 
the  letter  "k,"  etc.,   (F"ig.   ii6). 

Septum. — The  ?iasal  fossa;  are 
separated  from  each  other  by  the  sep-  \ 
turn.  This  septum  is  formed  (see 
Fig.  1 1 7)  by  the  triangular  cartilage 
in  front,  forming  the  cartilaginous  sep- 
tum, and  the  perpendicular  plate  of 
the  ethmoid  and  \'omer  behind,  form- 
ing the  bony  septum.  The  posterior 
edge  of  the  septum  is  formed  solely 
by  the  edge  of  the  vomer ;  it  can  readily  be  seen  with  the  rhinoscopic  mirror.  The 
affections  of  the  septum  are  hsematoma,  ulcer  and  abscess,  deviation  to  one  side, 
spurs  or  outgrowths,  and  it  may  be  the  site  of  nasal  hemorrhages.     Hcematomas  affect 

the  cartilage  of  the  septum  and  resemble 
those  of  the  ear.  They  are  usually  due 
to  traumatism  and  may  become  infected, 
forming  a  pus-like  detritus  or  abscess. 
They  can  readily  be  recognized  as  a 
fluctuating  swelling  on  the  septum,  one 
or  both  sides  being  affected. 

Deviations  of  the  septum  are  bend- 
ings  toward  one  side,  and  cause  serious 
obstruction  to  breathing.  They  are  prob- 
ably traumatic  in  origin  and  invoh'e  the 
cartilaginous  portion.  In  operating  for 
their  correction,  incisions  are  made 
through  the  cartilage  and  the  projecting 
part  pushed  toward  the  median  line.  In 
some  operations  care  is  taken  not  to  cut 
through  the  mucous  membrane  on  both 
sides,  as  well  as  through  the  cartilage. 
This  is  done  to  avoid  the  formation  of 
a  permanent  perforation  of  the  septum, 
the  presence  of  which  may  cause  a  very 
objectionable  whistling  sound  when  the 
patient  breathes.  As  the  mucous  mem- 
brane co\'ering  the  cartilage  is  thin,  great 

and  infeiTor  tOTbina7erexpo7ed"to  view.""  care  is  necessary  in  di\'iding  the  cartilage 

to  avoid  wounding  the  side  which  it  is  de- 
sired to  leave  intact.  The  triangular  cartilage  is  thin  at  its  centre  and  thick  at  its  edges. 
Spurs  are  usually  outgrowths  of  bone  or  cartilage  occurring  in  the  line  of 
juncture  of  the  cartilage  and  vomer.  On  the  floor  of  the  nose  the  nasal  crest  may 
project  quite  perceptibly  to  one  side;  a  cartilaginous  projection  may  likewise  occupy 
this  site.  As  these  spurs  are  found  on  the  anterior  edge  of  the  vomer,  they  some- 
7 


APPLIED     ANATOMY. 


times  form  a  distinct  ridge  of  bone  running  upward  and  backward.  If  the  spur  is 
short  in  extent,  the  farther  posterior  it  is  situated,  the  higher  up  it  is  on  the  septum. 
If  marked,  it  is  often  accompanied  by  deviation  of  the  septum  and  it  may  impinge 
on  the  lower  turbinated  bone  opposite  to  it.  These  spurs  are  usually  removed  by 
sawing.  A  narrow-bladed  saw  is  introduced  with  its  back  on  the  floor  of  the  nose 
and  the  spur  removed  by  sawing  upward  (Fig.  ii8). 

Epistaxis  or  bleeding  from  the  nose  is  said  to  occur  in  a  large  percentage  of 
the  cases  from  the  septal  branch  of  the  sphenopalatine  artery.  This  comes  from  the 
internal  maxillary  artery  through  the  sphenopalatine  foramen  and  passes  downward 
and  forward  as  the  nasopalatine  or  artery  of  the  septum.  It  anastomoses  below  with 
the  anterior  palatine  branch  of  the  descending  palatine  artery  as  it  comes  up  from 
the  roof  of  the  mouth  through  the  fo?'amen  of  Stenson  (incisor  foramen).  It  alsQ 
anastomoses  with  the  inferior  artery  of  the  septum,  a  branch  of  the  superior  coronary. 
The  bleeding  point  is  to  be  sought  for  low  down  on  the  anterior  portion  of  the 
cartilaginous  septum  near  the  anterior  nares.  Hemorrhage  can  be  stopped  by 
packing  only  the  anterior  or  both  the  anterior  and  posterior  nares. 


Triangular  cartilage 


Fig.  117. — Septum  of  the  nose. 

The  arteries  supplying  the  nasal  cavities  (Fig.  119)  come  from  three  directions  : 
superior — the  anterior  and  posterior  ethmoidal,  supplying  the  ethmoidal  cells,  the 
upper  portion  of  the  septum,  the  roof,  and  the  outer  wall  anteriorly;  inferior — the  septal 
branch  of  the  superior  coronary  artery  and  a  branch  of  the  descending  palatine  arterv 
coming  up  through  the  incisor  foramen;  posterior — the  sphenopalatine,  giving  its 
nasopalatine  branch  to  the  septum  and  also  supplying  branches  to  the  ethmoidal 
cells,  frontal  and  maxillary  sinuses,  and  outer  wall  of  nose,  the  Vidian  and  pterygo- 
palatine ^omg  to  the  posterior  portion  of  the  roof,  and  the  descending  palatine  ^wva^ 
branches  to  the  posterior  portion  of  the  inferior  meatus  and  posterior  end  of  the 
inferior  turbinated  bone. 

The  veins,  like  the  arteries,  are  in  three  sets:  the  superior  are  formed  by  the 
anterior  and  posterior  ethmoidal  and  some  smaller  veins  passing  upward  through  the 
foramen  in  the  cribriform  plate,  or  foramen  ca;cum,  to  the  longitudinal  sinus;  the 
infei-ior  communicate  with  the  facial  veins  through  the  anterior  nares;  the  posterior 
drain  upward  and  backward  through  the  sphenopalatine  foramen  into  the  pterygoid 
plexus. 

The  lymphatics  drain  either  anteriorly  on  the  face  or  posteriorly  through  the 
deep  lymphatics  of  the  neck.  Therefore,  acrid  secretions  causing  ulcerations  of  the 
anterior  nares  are  liable  to  be  accompanied  by  swelling  of  the  subma.xillary  lymphatic 


THE   NOSE. 


99 


nodes;    while  enlargement  of    the  deep  cervical  lymphatics  follows  disease  of    the 

deeper  nasal  cavities.  ,    ,  ,  .  t-i. 

Nasal  hvpertrophies  are  enlargements  of  the  nasal  mucous  membrane.  1  he 
mucous  membrane  of  the  nose  or  Schnciderian  membrane  has  columnar  ciliated  cells 
on  its  surface  and  mucous  cells  beneath.  It  is  prolonged  into  the  various  sinuses  and 
cavities  in  connection  with  the  nasal  foss£E.  The  membrane  on  the  upper  third  of 
the  septum,  the  uoper  portion  of  the  middle  turbinated,  and  the  superior  turbinated 
bone  contains  the  terminal  filaments  of  the  olfactory  nerve.  The  membrane  over 
the  lower  portion  of  the  septum,  over  the  lower  edge  of  the  middle,  and  the  greater 
part  of  the  inferior  turbinated  bones,  contains  a  venous  plexus  which  renders  it 
erectile.  On  the  slightest  irritation  this  portion  of  the  membrane  will  swell  and 
obstruct  the  passage  of  air  through  the  nostrils.  Repeated  swelling  of  the  membrane 
of  the  septum  produces  thickenings  of  the  septum,  which  if  anterior  may  be  seen 
through  the  nostrils,  and  if  posterior  by  the  rhinoscopic  mirror.      The  membrane 


Nasal  crest  and  septal  spurs. 


over  the  inferior  turbinated  bones  also  becomes  swollen  and  enlarged,  constituting,  if 
at  the  forward  end,  anterior  hypertrophy,  and  if  at  the  posterior  extremity,  posterior 
hypertrophy  fFig.  120).  They  can  be  readily  seen  through  the  nasal  speculum  ante- 
riorly and  by  the  rhinoscopic  mirror  posteriorly.  They  are  treated  by  applications  of 
acids,  as  chromic  and  trichloracetic,  by  the  electrocautery,  or  are  snared  off  with  the 
cold  snare.  Snaring  is  more  often  employed  in  reducing  posterior  hypertrophies,  but 
both  the  anterior  and  posterior  can  be  reached  by  an  electrocautery  point  or  a  knife 
introduced  through  a  speculum  in  the  anterior  nares. 

The  Outer  Wall. — The  outer  wall  has  on  it  the  three  turbinated  bones — 
superior,  middle,  and  inferior.  The  inferior  is  a  separate  bone,  but  the  middle  and 
superior  are  parts  of  the  ethmoid  bone  (Figs.  121  and  122). 

The  inferior  meatus  is  between  the  inferior  turbinated  bone  and  the  floor  of 
the  nose.  The  lachrvmonasal  dtcct  enters  this  meatus  just  below  the  anterior  end 
of  the  inferior  turbinated  bone.  It  j^ierces  the  mucous  membrane  obliquely,  being 
guarded  by  a  fold  called  the  valve  of  Hasner.  The  opening  is  not  visible  from  the 
anterior  nares  and  usually  it  is  impossible  to  introduce  a  probe  into  it  from  them. 


loo  APPLIED    AXATO^IY. 

The  middle  meatus  is  between  the  middle  and  inferior  turbinated  bones. 
The  mucous  membrane  co\'ering  the  middle  turbinated  bone  lies  closer  to  it  than 
does  that  of  the  inferior  turbinated  bone,  so  that  it  is  comparati-\-ely  rare  that  treat- 
ment is  necessar}'  to  reduce  it. 

Polypi  usually  ha\e  their  origin  in  this  meatus.  Beneath  the  middle  turbinated 
bone  on  the  outer  wall  of  the  nose  and  only  to  be  seen  after  removal  of  the  bone, 


Posterior  ethmoidal 


Triangulsr  cartilage 


Septal  branch  of, 
superior  coronary' 


Branch  from  the  descending  palatine 
Fig.  119. — .-\rteries  supplying  the  septum  of  the  nose. 

there  is,  just  anterior  to  its  middle,  a  rounded  eminence,  the  bulla  ethmoidalis.  In  it 
is  an  opening  for  the  middle  ethmoidal  cells.  Imjnediately  in  front  is  a  slit,  the 
hiatus  semilunaris,  into  which  open  the  ma.xillar\-  sinus  {antrum  of  Highmore)  and 
the  anterior  ethmoidal  cells.  The  hiatus  is  continued  above  as  the  infundibulum, 
which  enters  the  frontal  sinus.     The  relation  between  the  hiatus  and  the  opening  into 


Anterioi  nasal  h\-pertrophy 


Posterior  nasal  hypertrophy 
Fig.  120. — View  of  anterior  and  posterior  hypertrophies  of  the  inferior  turbinate. 

the  maxillary  sinus  is  such,  in  some  cases,  that  it  is  possible  for  pus  originating  in 
the  frontal  sinus  to  discharge  into  the  maxillary  sinus.  A  knowledge  of  the  relation 
of  these  parts  is  essential  to  those  desirous  of  treating  nasal  diseases. 

The  superior  meatus  is  comparatively  small  and  lies  above  the  middle  tur- 
binated bone.  At  the  anterior  edge  of  the  superior  turbinated  bone  is  the  opening 
for  the  posterior  ethmoidal  cells.     Sometimes  there  are  two  or  three  superior  turbinals. 


THE    XOSE. 


The  spheno-ethmoidal  x&Qess  is  the  cleft  above  the  superior  turbinated  bone;  into 
it  opens  the  sphenoidal  sinus.  In  order  to  examine  and  reach  the  openings  of  any 
of  these  sinuses,  it  is  practically  necessary  to  take  away  a  part  or  all  of  the  middle 
turbinated  bone  before  they  can  be  exposed  to  view.  When  this  is  done,  they  can 
be  probed,  washed  out,  drained,  etc.  (see  Fig.  125). 

The  frontal  sinuses  begin  to  develop  about  puberty.  They  occupy  the  lower 
anterior  portion  of  the  frontal  bone.  Their  size  and  extent  vary  considerably.  The 
usual  size  is  from  the  nasion  below  to 
the  upper  edge  of  the  superciliary  ridges 
above  and  laterally  from  the  median  line 
to  the  supra-orbital  notch.  These  limits 
may  be  e.xceeded  considerably.  They 
may  go  as  far  out  as  the  middle  of  the 
upper  edge  of  the  orbit  or  even  nearly 
to  the  temporal  ridge.  The  anterior  and 
pbsterior  walls  are  separated  a  distance 
of  o.  5  to  I  cm.  The  distance  which  they 
extend  back  over  the  orbit  and  upward 
also  \'aries.  The  two  sinuses  are  sepa- 
rated by  a  partition  which  is  often  to  one 
side  of  the  median  line,  so  that  it  is  apt 
to  be  encountered  in  opening  the  sinus 
through  the  forehead.  The  two  cells 
often  differ  greatly  in  size  and  may  be 
divided  into  various  recesses  by  incom- 
plete septa.  They  have  the  infundib- 
ulum  as  their  lower  extremity,  which 
passes  into  the  hiatus  semilunaris  be- 
neath the  middle  turbinated  bone  and  empties  into  the  middle  meatus.  The  frontal 
sinuses  are  frequently  the  seat  of  suppurative  inflammation.  This  gives  rise  to 
pain  and  tenderness  in  the  supra-orbital  region  and  to  a  discharge  from  the  cor- 
responding nostril.  This  discharge  can  be  seen  coming  from  beneath  the  anterior 
extremity  of  the  middle  turbinated  bone.  Owing  to  the  proximity  of  the  opening 
into  the  maxillary  sinus,  pus,  coming  down  the  hiatus  from  the  frontal  sinus,  may 


Frontal  sinus 

Anterior  ethmoidal  cell 
Middle  ethmoidal  cells 

Posterior  ethmoidal  cells 

Sphenoidal  sinus 

Bulla  ethmoidalis 
Superior  turbinate 
Middle  turbinate  (anterior 
half  removed) 


Hiatus  semilunaris 


Opening  of  1 


I  y       Opening  into  Inferior  turbinate 

\if        maxillary  sinus 

Fig.  12  2. — View  of  outer  wall  of  the  nose  and  accessory  cavities. 

pass  into  the  maxillary  sinus,  thus  simulating  disease  of  that  cavity.  In  order'  to 
wash  out  the  sinus,  cocaine  mav  be  first  applied  to  shrink  the  nasal  membrane  :  then 
sometimes  one  is  able  to  pass  a  probe  or  irrigating  tube  into  the  hiatus  semilunaris 
and  thence  up  into  the  sinus.  By  removing  the  anterior  extremity  of  the  middle 
turbinated  bone  access  to  the  hiatus  semilunaris  is  more  readily  obtained.  In  cer- 
tain cases  the  frontal  sinus  is  opened  either  through  the  supra-orbital  region  or 
entered  through  the  roof  of  the  orbit  at  its  inner  upper  corner.     The  glabella  is  the 


APPLIED    AXATO-MY. 


depression  in  the  median  line  separating  the  superciHary  ridges.  In  operating  on 
the  sinus  from  in  front,  the  opening  is  to  be  made  just  to  the  outer  side  of  the  gla- 
bella in  order  to  a^'oid  the  septum  between  the  sinuses.  In  curetting  the  sinus,  the 
thinness  of  the  upper  and  posterior  -wall  separating  it  from  the  brain,  and  of  the 
lower  wall  or  roof  of  the  orbit,  should  be  borne  in  mind,  otherwise  they  are  apt  to  be 
perforated.      The  sinus  may  be  divided  into  recesses  by  partial  septa  projecting  from 


Figs.  123   and   124 — Two  views  of  the  frontal   sinus,  sho-ning  variation  in  size  in  different  individuals.     The 
anterior  wall  has  been  cut  away  to  expose  the  interior  of  the  sinus. 

the  sides.  Drainage  into  the  nose  is  obtained  by  passing  an  instrument  from  above 
downward  through  the  anterior  ethmoidal  cells.  In  entering  the  sinus  from  below 
from  the  outside,  the  opening  is  made  at  the  extreme  anterior  upper  edge  of  the 
orbit,  perforating  the  bone  in  a  direction  upward  and  inward.  The  opening  into  the 
sinus  may  be  enlarged  from  within  the  nose  by  first  inserting  a  probe  to  protect  the 

brain  and  posterior  wall  and  then  chisel- 
ling or  gnawing  away  the  bone  in  front 
so  that  easy  access  is  obtained  through 
the  nose  for  drainage,  packing,  etc. 

The  ethmoidal  sinuses  or  cells, 
three  in  number  on  each  side,  anterior, 
middle,  and  posterior,  lie  between  the 
sphenoidal  sinus  posteriorly,  and  the 
lower  extremity  of  the  frontal  sinus  an- 
teriorly. The  anterior  cells  lie  in  front 
of  or  just  above  the  hiatus  and  open 
into  it.  The  middle  lie  just  posterior  to 
the  hiatus  and  open  into  the  outer  wall 
of  the  middle  meatus,  perforating  the 
hdla  ethmoidalis,  ^x-hich  is  a  rounded 
projection  on  the  outer  wall  beneath  the 
middle  turbinated  bone.  The  posterior 
cells  open  still  farther  back  beneath  the 
superior  turbinated  bone  in  the  superior 
meatus.  In  disease  of  these  cells,  pus 
from  the  middle  and  anterior  ones  will 
show  in  the  middle  meatus;  from  the 
posterior  cells  in  the  superior  meatus.  In  this  latter  case  it  is  to  be  detected  pos- 
teriorly by  means  of  the  rhinoscopic  mirror.  Access  to  the  cells  is  obtained  by 
removing  the  middle  turbinated  bone.  This  is  done  by  di\iding  it  into  two  pieces 
by  a  trans\'erse  cut  with  forceps  or  scissors  and  then  remo\-ing  the  two  halves  with 
a  snare.     By  means  of  probes,  curettes,  and  forceps,  the  openings  into  the  cells  may 


Fig.  125. — Probes  introduced  into  the  frontal,  max- 
illary, and  sphenoidal  sinuses.  The  anterior  portion  of  the 
middle  turbinate  has  been  removed. 


THE    NOSE. 


103 


be  discovered  and  enlarged  as  thought  necessary.  The  region  of  the  ethmoidal  cells 
is  that  from  which  mucous  polypi  of  the  nose  take  their  origin.  They  are  a  common 
accompaniment  of  suppuration  of  the  accessory  nasal  cavities.  They  are  usually 
removed  by  snares  introduced  through  the  anterior  nares  or  more  rarely  by  forceps. 
Caries  affecting  the  anterior  cells  may  extend  into  the  orbit  and  the  pus  may  form  a 
fluctuating  tumor  above  the  inner  canthus  of  the  eye.  Care  should  be  taken  not  to 
mistake  a  meningocele  for  such  a  tumor. 

The  sphenoidal  sinuses  are  the  most  posterior,  lying  still  farther  back  than 
the  ethmoidal.  They  open  into  the  spheno-ethmoidal  recess  above  and  posterior 
to  the  superior  turbinated  bone.  Discharge  from  them  goes  into  the  pharynx  and  is  to 
be  seen  with  the  rhinoscopic  mirror.  They  can  be  reached  by  first  removing  the 
middle  turbinated  bone  and  then  introducing  a  probe  upward  and  backward  from  the 
anterior  nares  for  a  distance  of  7.5  cm.  (3  in. )  in  women  and  8  cm.  in  men.  They  can 
be  drained  by  cutting  away  their  anterior  wall  with  punch  forceps  introduced  through 
the  anterior  nares. 

The  maxillary  sinus  lies  beneath  the  orbit  and  to  the  outer  side  of  the  nasal 
fossse.  It  is  the  seat  of  tumors,  often  malignant,  and  inflammation;  the  latter 
accompanied  by  an  accumulation  of  mucus  or 
pus.  The  walls  of  the  sinus  are  thin,  so  we 
find  tumors  bulging  forward,  causing  a  protrusion 
of  the  cheek.  They  press  inward  and  obstruct 
the  breathing  through  that  side  of  the  nose,  or 
they  push  upward  and  cause  protrusion  of  the 
eye  by  encroaching  on  the  orbit.  In  operating 
on  these  tumors,  the  superior  maxilla  is  usually 
removed;  the  lines  of  the  cuts  through  the  bones 
being  shown  in  Fig.  64.  In  prying  the  bone 
down  posteriorly,  it  may  not  be  torn  entirely  away 
from  the  pterygoid  processes  and  some  plates  of 
bone  may  be  left  attached.  This  should  be  borne 
in  mind  in  operating  for  malignant  growths.  The 
sphenoidal  cells  are  behind  the  upper  posterior 
portion  of  the  ma.xillary  sinus,  therefore  in.  oper- 
ating on  Meckel's  ganglion,  if  too  much  force  is 
used  in  breaking  through  the  posterior  wall  of 
the  antrum,  the  instrument  may  pass  across  the 
sphenomaxillary  fossa,  a  distance  of  about  3  mm. , 
and  open  the  sphenoidal  sinus. 

The  infra-orbital  nerve  is  usually  separated 
from  the  cavity  of  the  sinus  by  a  thin  shell  of 
bone.  At  the  upper  anterior  portion  of  the  sinus 
there  may  be  a  small  cell  between  the  bony  canal 

in  which  the  nerve  runs  and  the  bony  floor  of  the  orbit.  The  superior  dental  ner^^es 
reach  the  upper  teeth  usually  by  going  through  minute  canals  in  the  bone,  but  some- 
times, particularly  the  middle  set  supplying  the  bicuspid  teeth,  may  run  directly  beneath 
the  mucous  membrane,  and  thus  be  irritated  by  troubles  originating  within  the  sinus. 

The  inflammatory  and  infectious  diseases  of  the  sinus  originate  either  by  extension 
from  the  nose  or  the  teeth.  The  sinus  opens  into  the  nose  by  a  slit-like  opening  into  the 
middle  meatus  about  its  middle.posterior  to  the  hiatus  semilunaris  and  2. 5  cm.  above  the 
floor  of  the  nose.  When  the  opening  is  close  to  the  hiatus,  liquids  may  run  into  it  from 
the  hiatus.  The  bone  beneath  the  hiatus  and  opening  almost  down  to  the  floor  of  the 
nose  is  quite  thin,  so  that  the  sinus  can  readily  be  drained  by  thrusting  a  trocar  and  can- 
nula through  the  outer  wall  of  the  nose  into  the  sinus  just  below  the  hiatus  semilunaris. 
The  sinus  is  also  opened  from  the  front  through  the  canine  fossa  to  the  outer  side  of 
the  canine  tooth.  This  opening  affords  direct  access  to  the  cavity,  but  is  some  distance 
above  the  floor,  thus  it  does  not  drain  the  cavity  completely.  The  roots  of  the  i:pper 
teeth  project  into  the  antrum  forming  elevations,  usually  covered  by  a  thin  plate  of  bone. 
This  is  particularly  the  case  of  the  first  and  second  molars.  Disease  of  the  roots  of  these 
teeth  frequently  infects  the  antrum  and  drainage  is  often  made  through  their  sockets. 


APPLIED    ANATOMY. 


THE   MOUTH   AND   THROAT. 

The  lips  are  formed  mainly  by  the  orbicula7'is  oris  muscle  with  its  subdivisions 
and  the  accessory  facial  muscles  (buccinator,  levator  and  depressor  anguli  oris, 
levator  labii  superioris,  levator  labii  superioris  aleeque  nasi,  the  zygomaticus  major 
and  minor,  and  the  depressor  labii  inferioris).  The  orbicularis  oris  is  attached  to 
the  superior  maxilla  in  the  incisor  fossa  above  the  second  incisor  tooth  and  also 
above  to  the  septum.  In  the  lower  lip  it  is  attached  to  the  mandible  beneath  the 
second  incisor  tooth.  The  lips  contain,  beside  muscular  tissue,  some  areolar  tissue, 
arteries,  veins,  and  lymphatics.  The  muscular  fibres  are  inserted  into  the  skin.  The 
mucous  membrane  lining  the  lips  has  lying  beneath  it  some  mucous  glands.  They 
sometimes  become  enlarged  and  form  small,  shot-like,  cystic  tumors  containing  mucus.  ' 

Affections  of  the  Lips. — The  lips  are  affected  by  wounds,  angioma  or  blood 
tumor,  cancer  [epithelioma),  and  clefts  {harelip).  Wounds  of  the  lip  when  properly 
approximated  heal  readily  on  account  of  the  free  blood  supply.      The  arteries  sup- 


Auricularis  anterior     ^i&X^ 


Auricularis  postei 

ZygoraaUcus  major 
Zygomaticu: 

Lei'ator  anguii  oris 

Levator  labii  supei  loi  is 

Buccinator 

Risorius- 


4 Corrugator  supercil 

OibiLUlaris  palpebr; 

-^Oihit-il  part  of  sani' 
'  -PMimidalisnasi 


Depressor  angiili  oris 
Depressor  labii  inferi. 
_Le\ator  menti 


Fig.  127. — -Superficial  dissection,  showing  the  muscles  of  the  head  and  face.     (Piersol.) 


plying  the  lips  are  the  siperior  and  inferior  coronary  branches  of  the  facial.  They 
are  given  off  about  opposite  the  angle  of  the  mouth  and  pierce  the  muscle  to  run 
beneath  the  mucous  membrane  about  midway  betwen  the  edge  of  the  lip  and  its 
attachment  to  the  gums  or  nearer  the  free  border  of  the  lip.  Therefore,  in  operating 
on  the  lip,  the  artery  should  be  looked  for  in  this  situation  and  not  toward  the  skin 
surface  or  in  the  substance  of  the  lip.  The  superior  coronary  sends  a  branch  to  the 
nasal  septum,  called  the  inferior  artery  of  the  septum.  In  the  sulcus  between  the 
lower  lip  and  chin  lies  the  inferior  labial  artery.  The  bleeding  from  this  branch  is 
not  so  free  as  that  from  the  coronary  arteries,  because  the  anastomosis  across  the 
median  line  is  not  so  marked. 

Angioma. — The  blood-vessels,  mainly  the  veins,  of  the  lips  sometimes  become 
enlarged,  forming  a  large  protrusion.  This  may  be  noticed  at  or  soon  after  birth 
as  a  dusky  blue,  slightly  swollen  spot  on  the  lip.  As  the  child  grows  the  swelling- 
enlarges.  Sometimes  it  enlarges  rapidly  and  operation  is  necessary  to  check  its 
growth;  otherwise  it  may  involve  a  large  portion  of  the  face  and  prove  incurable.  It 
is  composed  of  dilated  veins  with  thin  walls  and  large  lumen.  It  does  not  pulsate 
and  disappears  under  pressure,  only  to  return  when  this  is  removed.  It  is  treated 
by  excision.  The  thin  skin  is  dissected  off  and  the  growth  cut  away  from  the  tissues 
beneath,  the  bleeding  being  controlled  by  pressure,  hsemostats,   and  ligatures.      In 


THE   MOUTH   AND   THROAT.  105 

the  case  figured,  the  facial  vein,  as  it  crossed  the  mandible,  and  the  transverse  facial 
vein  were  obliterated  by  means  of  acupressure  pins  passed  beneath  them,  and  the 
growth  was  excised. 

Cancer  or  epithelioma  of  the  Hp  almost  always  affects  the  lower  and  not  the 
upper  lip.      The  disease  extends  through  the  lymphatics.      These  pass  down  and  out 


/    \  1/ 


Fig.  12S. — .'\ngioma  invol 
lip  in  a  child. 


ing  the  right  half  of  the  upper 
(Personal  sketch.) 


-Single  harelip. 


from  the  lips  to  the  submaxillary  lymph-nodes  and  then  to  the  nodes  along  the 
great  vessels  of  the  neck.  It  is  in  these  regions  that  lymphatic  infection  is  usually 
seen.  The  middle  of  the  lower  lip  is  drained  into  a  node  in  the  submental  region  in 
front  of  the  subma.xillary  nodes. 
This  also  is  sometimes  involved. 
In  operating  for  cancerous 
growths  it  is  advisable  to  re- 
move all  nodes  from  both  the 
submental  and  submaxillary  tri- 
angles. 

Cleft  or  harelip  is  so  named 
from  its  resemblance  to  the  lip 
of  a  hare.  It  is  a  deformity  due 
to  lack  of  development,  in  which 
the  lip  is  cleft  or  split  from  the 
mouth  up  into  the  nostril,  and 
sometimes  even  back  through 
the  hard  and  the  soft  palate. 
When  the  cleft  is  slight,  it  may 
not  reach  the  nostril.  It  is 
practically  always  to  one  side  of 
the  middle,  going  toward  one 
nostril.  Sometimes  the  harelip 
is  double,  involving  both  sides. 
In  such  cases  the  bone  between 
the  two  clefts  may  protrude.  In 
the  development  of  the  face,  the 
frontonasal  process  comes  down 
from  above  to  form  the  middle 
portion  of  the  nose,  upper  lip, 
and  upper  jaw.  It  forms  a  bone  known  as  the  premaxilla  and  bears  the  incisor  teeth. 
From  the  sides  spring  the  nasal  and  maxillary  processes.  These  join  together  as  one 
process  and  grow  toward  the  premaxilla.     If  this  process  fails  to  reach  the  premaxillary 


-Double  harelip,  phowing  the  proiecting  premaxilla 


io6 


APPLIED    AX  ATOMY. 


bone,  a  cleft  is  left  constituting  harelip.     If  both  processes  fail  to  reach  the  premaxilla, 
a  double  harelip  is  formed;  the  cleft  may  extend  through  the  hard  and  the  soft  palate — 

/Frortona^al  process 
/Aledial  nasal  process 


/\-  a!  pit 

Lateral  nasal  process 

Lachr^Tnonasal  furrow 


Maxillary  process 
"First  visceral  arch 
Mandibular  process 
First  visceral  furrow 
■Second  \-isceral  arch 
■Second  \-isceral  furrow 
-Third  ^-isceral  arch 


Fig.  131. — Frontal  view  of  human  foetus  about  four  weeks  old.     (After  His.) 

the  cleft  palate  may  alone  be  present  as  seen  in  Fig.  139  (see  page  112).    In  operating  for 
harelip,  the  two  sides  of  the  cleft  are  freshened  and  sewed  together,  thus  closing  the  cleft. 


Fig.  132. — Parali'sis  of  depressor  labii  inferioris  from  section  of  the  lower  filament  of  the  facial  nerve.    (McDowd.) 

Pai'alysis  of  the  lips  is  due  to  interference  with  the  functions  of  the  seventh  nen^e. 
The  muscles  of  the  face  and  lip  are  supplied  by  the  seventh  or  facial  nerve.  This  is 
frequently  paralyzed,  for  ouing  to  its  tortuous  passage  through  the  temporal  bone  in 
the  canal  of  Fallopius  it  is  injured  in  fractures  of  the  base  of  the  skull  and  becomes 


THE    MOUTH    AND    THROAT. 


107 


affected  from  middle  ear  disease  or  neuritis.  Wfien  paralyzed,  the  muscles  of  the 
lips,  both  upper  and  lower,  on  the  affected  side,  droop.  The  drooping  of  the  lower  lip 
may  allow  the  saliva  to  run  out  of  the  mouth.  It  is  also  impossible  for  the  patient 
to  pucker  his  mouth,  as  in  whistling.  If  the  lesion  of  the  facial  nerve  is  inside  the 
skull  and  not  in  the  Fallopian  canal,  Xh^  great  petrosal  nerve  and  some  of  the  palatal 
muscles  will  be  paralyzed,  the  voice  will  be  altered  and  swallowing  interfered  with. 

The  depressor  labii  inferioris  instead  of  receiving  its  ner\'e  supply  from  the  supra- 
mandibular  branch  of  the  facial,  frequently  is  supplied  by  the  inframandibular  branch; 
pressure  or  injury  of  this  branch  in  enlargements  of  or  operations  on  the  submandib- 
ular lymph-nodes  has  produced  paralysis  of  the  muscle  with  a  peculiar  alteration  of 
the  facial  expression,  well  shown  (see  Fig.  132)  by  a  case  of  Dr.  McDowd  {Annals  of 
Surgery,  July,  1905). 

Mouth. — Surface  Anatomy. — In  looking  into  the  mouth,  one  sees  the  tongue 
below  and  the  roof  above,  surrounded  in  front  and  on  the  sides  by  the  teeth.  On  each 
side  are  the  inner  surfaces  of  the  cheeks  and  posteriorly  are  seen  the  uvula,  the 


.Hard  palate 

Junction  of  the 
'and  soft  palates 

hard 

■  Soft  palate 

Uvula 

-Anterior  pillar 
-Posterior  pillar 

of  fauces 
of  fauces 

-  Tonsil 

Fig.  133. — Interior  of  the  mouth. 

arches  of  the  palate,  and  the  pharynx.  On  the  mucous  membrane  of  the  cheek, 
opposite  the  second  upper  molar  tooth,  is  a  small  papilla  in  the  top  of  which  opens 
the  duct  of  the  parotid  gland.  A  small  probe  can  be  inserted  into  it  and  passed 
outward  and  backward  toward  the  gland. 

Tongue. — The  tongue  is  covered  with  a  mucous  membrane  which  is  modified 
skin;  therefore  it  is  subject  to  the  same  diseases  as  the  skin.  It  is  covered  with 
papillae  of  three  kinds — the  filiform,  fungiform,  and  circumvallate.  The  filiform 
are  the  smallest  and  most  numerous  and  form  a  sort  of  ground-work  in  which  the 
others  are  imbedded.  The  fungiform  are  larger  and  fewer  in  number  and  are  scattered 
on  the  dorsum,  sides,  and  tip  of  the  tongue  among  the  filiform.  The  circumvallate, 
seven  to  twelve  in  number,  form  a  V-shaped  row  at  the  base  of  the  tongue.  In  the 
eruptive  fevers,  particularly  scarlet  fever,  the  tongue  gets  ^-ery  red  and  the  papillae 
become  enlarged,  forming  what  is  known  as  the  strawberry  or  raspberry  tongue. 
Just  beyond  the  apex  of  the  circumvallate  papillae  in  the  median  line  is  the  forame^i 
c(Bciim.  It  is  sometimes  patulous  for  a  short  distance  and  is  the  upper  extremity  of 
the  remains  of  the  thyroglossal  duct. 


loS 


APPLIED    AXATOMY. 


On  the  posterior  portion  of  the  tongue  behind  the  circumvallate  papillae,  on 
each  side  of  the  median  line,  is  a  mass  of  adenoid  tissue  which  forms  what  is  known 
as  the  lingual  toiisil.  It  sometimes  becomes  hypertrophied  and  is  then  cut  off  with 
a  specially  cur^-ed  tonsillotome  just  as  is  done  with  enlarged  faucial  tonsils.  Run- 
ning from  the  base  of  the  tongue  to  the  epiglottis  are  three  folds,  called  the  median 
and  lateral  glosso-epigloftic  folds. 

In  the  middle  of  the  dorsum  of  the  tongue  is  a  furrow;  this  is  caused  bv  the 
septum  binding  the  middle  of  the  tongue  down  and  allowing  the  muscles  to  rise  on 
each  side. 

On  turning  the  tip  of  the  tongue  up  (Fig.  135),  a  fold  of  membrane,  ^Q.frcBnum, 
is  seen  extending  from  the  under  surface  to  the  floor  of  the  mouth  beneath.  In  new- 
born children,  this  frsenum  appears  sometimes  to  be  too  short,  hence  the  name  tongv^- 
tie.      In  cutting  it,  the  split  end  of  a  grooved  director  is  placed  o\'er  the  freenum 


Fossa  of  Rosenmulle 
Eustachian  tube 


Foramen  csecum 
ingual  tonsil 


Cuneiform  tubercle  (Wrisberg) 


Comiculate  tubercle 
(Santo  rini) 


Sinus  pyriformis 


Cricoid  cartilage 


and  the  tongue  pushed  back.  This  makes  the  frasnum  tense  and  it  can  readily  be 
snipped  with  the  scissors.  Care  should  be  taken  not  to  cut  too  deeply,  or  the  ranine 
artery  may  be  cut  and  cause  troublesome  bleeding.  Running  across  the  floor  of  the 
mouth,  between  the  teeth  and  tongue,  parallel  to  the  ah-eolus,  is  the  sublingual  ridge, 
formed  by  the  sublhigiial gland.  This  gland  lies  on  the  mylohyoid  muscle  beneath 
and  the  lower  jaw  in  front.  On  each  side  of  the  fraenum  on  the  sublingual  ridge  is  a 
papilla  into  which  the  duct  of  the  subma.xillarv  gland,  llliarton'  s  duct,  opens.  Open- 
ing into  Wharton's  duct,  or  by  a  separate  duct  into  the  same  papilla,  is  the  duct  of 
the  sublingual  gland,  called  the  dud  of  Rivinus  or  Bartholin.  The  superficial  por- 
tion of  the  gland  opens  on  the  sublingual  ridge  to  the  outer  side  of  the  papilla  b)'  a 
number  of  small  ducts,  called  the  ducts  of  Walthcr. 

Ranida  is  the  name  given  to  a  cj'st  occurring  in  connection  with  the  sali\ary 
glands.      Such  cysts  invoh-ing  the  parotid  gland  are  quite  rare,  so  that  the  term 


THE   MOUTH   AND   THROAT. 


109 


is  usually  restricted  to  those  of  the  submaxillary  and  sublingual  glands.  The 
mylohyoid  muscle  forms  the  floor  of  the  mouth  and  these  cysts  lie  on  it  beneath 
the  tongue  and  between  the  tongue  and  the  gums  (Fig.  136).  If  the  cyst  is  large  it 
causes  a  protrusion  or  swelling  beneath  the  jaw.  The  bulk  of  the  submaxillary  gland 
lies  on  the  side  of  the  mylohyoid  muscle  nearest  the  skin;  only  a  small  portion  of  it 


Sublingual  ridge 

Orifice  of 
sublingual  and 
submaxillary  ducts 


Fig.   T35. — Under  surface  of  tongue  and  floor  of  mouth. 

winds  around  the  posterior  edge  of  the  muscle.  Therefore,  cysts  involving  the  sub- 
stance of  the  gland  would  show  in  the  submaxillary  region  of  one  side.  If,  howexer, 
the  duct  were  obstructed  (as  by  a  calculus)  it  would  form  a  cyst,  which  would  bulge 
into  the  mouth  beneath  the  tongue  and  be  called  a  ranula.  The  sublingvial  gland  is 
usually  the  starting  point  of  these  cysts,  and  it  will  be  seen  that  as  they  enlarge  they 


Fig.  136.— Subl 


//~--Cyst 


photograph  by  Dr.  Ashhurst.) 


push  the  ranine  artery  with  the  tongue  backward  and  are  only  covered  by  the  mucous 
membrane.  On  this  account  there  is  little  or  no  danger  in  operating  on  them. 
They  are  either  dissected  out  or  the  front  wall  of  the  cyst  cut  away  and  the  interior 
cauterized  or  packed  with  gauze  to  promote  the  formation  of  granulations.  The 
jaw-bone  is  in  front  of  them  and  the  mylohyoid  muscle  beneath.  Posteriorly  lies  the 
duct  of  the  submaxillary  gland  and  the  ranine  artery. 


no  APPLIED    ANATOMY. 

Mucous  cysts  can  occur  from  the  mucous  glands  of  the  mouth  and  tongue  itself. 
There  is  a  gland  on  the  under  side  of  the  tip  of  the  tongue,  usually  larger  than  the 
others,  called  the  anterior  lingua/  gland  or  gland  of  Nuhn.  As  a  rule,  these  mucous 
cysts  are  small  and  are  felt  as  hard  rounded  bodies  beneath  the  mucous  membrane. 
Dermoid  cysts  occur  in  connection  with  the  tongue  but  very  rarely. 

Carcinoma  of  the  tongue  is  a  moderately  frequent  disease  and  as  the  tongue  is 
covered  by  modified  skin,  the  cancer  is  of  epithelial  type.  It  begins  on  the  surface 
of  the  tongue  either  by  a  change  in  the  epithelial  covering  or  else  in  fissures  or  ulcers 
at  its  edges. 

The  lymphatics  of  the  tongue  pass  to  the  subma.xillary  nodes  beneath  the  jaw 
and  thence  to  the  deep  cervical  nodes  along  the  great  vessels  or  directly  to  the  latter 
without  passing  through  the  submaxillary  nodes.  If  the  disease  exists  for  any  length 
of  time,  these  kre  the  nodes  that  become  infected.  They  are  only  to  be  reached  by 
an  incision  in  the  neck. 

The  arteries  of  the  tongue  are  the  lingual  and  its  bi-anckes,  the  Iiyoid,  the 
dorsalis  Ungues,    sublingual,    and  ranine.      In  removing    the   tongue,   the   lingual 


Anterior  lingual  gland 


Orifice  of  submaxillary 
and  sublingual  glands 


Sublingual  gland 


Fig.  137. — Under  surface  of  the  tongue,  mucous  membrane  removed. 

artery  on  the  side  to  be  removed  is  sometimes  ligated  in  the  neck ;  this  cuts  of!  the 
blood  supply  to  that  side  and  there  is  practically  no  bleecUng.  There  is  very  little 
anastomosis  between  the  vessels  of  the  two  sides  of  the  tongue.  The  arteries  run 
lengthwise  through  the  tongue,  so  that  in  glossitis  or  inflammatory  swelling  of  the 
tongue,  incisions  should  always  be  made  longitudinally  into  it. 

The  ligation  of  the  lingual  artery  will  be  found  described  in  the  section  on  the 
neck.  As  the  lingual  artery  passes  above  the  hyoid  bone,  it  gives  off  its  first  branch, 
the  hyoid.  It  is  quite  small  and  goes  above  the  hyoid  bone  superficial  to  the  hyo- 
glossus  muscle.  The  lingual  then  goes  beneath  the  hyoglossus  muscle  and  near  the 
posterior  edge  gives  off  its  second  branch  or  dorsalis  lingucB. 

In  excision,  the  tongue  is  usually  cut  through  on  the  distal  side  of  the  dorsalis 
lingufe  artery.  When  this  is  the  case,  the  bleeding  which  occurs  from  the  branches 
of  the  dorsalis  linguae  is  not  marked  because  it  is  not  a  large  artery. 

In  order  to  draw  the  tongue  out,  it  must  be  loosened  posteriorly  by  cutting  the 
anterior  pillars  of  the  fauces  and  palatoglossus  muscle,  and  anteriorly  at  the  fraenum 
by  cutting  the  geniohyoglossus  muscle.     By  drawing  the  tongue  up,  the  ranine  artery 


THE    MOUTH    AND    THROAT. 


is  drawn  out  of  the  way  and  there  will  be  only  slight  bleeding  from  small  branches 
of  the  sublingual,  which  comes  from  the  main  trunk  at  the  anterior  edge  of  the  hyo- 
o-lossus  muscle.  From  this  point  forward  to  the  tip,  the  lingual  artery  is  called  the 
ranine.  The  tongue  having  been  loosened  and  pulled  out,  Mr.  Jacobson  makes  a 
transverse  cut  through  the  mucous  membrane  behind  the  growth  and  then,  by  push- 
ing the  tissues  aside  with  a  blunt  instrument,  exposes  the  lingual  nerve  and  artery 
lying  together  beneath  the  mucous  membrane.  The  artery  is  then  tied  and  the 
growth  removed. 

In  order  to  secure  any  bleeding  points  after  the  tongue  has  been  cut  away,  the 
floor  of  the  mouth  can  be  raised  and  pushed  forward  by  the  fingers  beneath  the  chin. 


Hypoglossal 


Geniohyoglossus  muscle 
Ranme  artery 


SubliriRUal  gland 


Submaxillar\  duct 

Fig.  138. — The  cheek  has  been  split,  the  tongue  drawn  forward,  and  the  mucous  membrane  removed  from 
its  under  surface,  exposing  the  ranine  artery  and  vein,  the  lingual  and  hypoglossal  nerves,  the  sublingual  gland, 
the  subma.xillary  ganglion,  and  the  duct  of  the  submaxillary  gland. 

This  brings  the  stump  into  view  and  within  reach.  If  lymphatic  nodes  are  to  be 
removed,  they  must  be  sought  for  by  an  additional  incision  on  the  outside  beneath 
the  jaw. 

The  roof  of  the  mouth  is  formed  by  the  hard  palate  and  the  soft  palate ;  the 
former  comprising  about  three-fourths  and  the  latter  one-fourth.  The  hard  or  bony 
palate  is  composed  in  its  anterior  two-thirds  of  the  palatal  processes  of  the  superior 
maxillary  bones,  and  in  its  posterior  third  of  the  palatal  bones.  In  the  median  line 
close  to  the  incisor  tooth,  in  the  dried  skull,  is  the  anterior  or  nasopalatine  foramen. 
This  is  subdivided  into  four  foramina,  two  lateral  and  two  anteroposterior.  The 
former,  called  the  foramina  of  Stenson,  transmit  the  terminal  branches  of  the  de- 
scending palatine  arteries;  of  the  latter,  csWedthe  foramina  of  Scarpa,  the  anterior  one 
transmits  the  left  nasopalatine  nerve,  and  the  posterior  one  the  right  nasopalatine 
nerve.  The  soft  tissues  of  the  roof  of  the  mouth  are  thicker  than  they  appear  to  be, 
so  that  when  they  are  raised,  as  in  operating  for  cleft  palate,  they  form  quite  a  thick 
layer.  Infection  of  the  roof  of  the  mouth  when  it  occurs  is  usually  by  extension  from 
neighboring  diseased  teeth,  abscesses  being  sometimes  produced. 

The  blood  supply  of  the  roof  is  of  importance  in  relation  to  the  operation  for  cleft 
palate  {staphylorrhaphy')  (Fig.  139).  The  blood  comes  anteriorly  from  the  nasopala- 
tine arteries  and  posteriorly  from  the  descending  palatine  arteries,  which  come  down 


112  APPLIED    ANATOiMY. 

through  the  pterygopalatine  canal  from  the  internal  maxillary  artery  and  make  their 
appearance  on  the  hard  palate  at  the  posterior  palatine  foramen.  This  foramen  is  on 
the  roof  of  the  mouth  opposite  the  last  molar  tooth  and  0.5  cm.  to  the  inner  side  and 
in  front  of  the  hamular  process  TFig.  140).     This  hamular  process  can  be  felt  just  pos- 


Opening  of  the 
pharyngeal  pouch 


ryngeal  pouch  on  the  posterior  wall. 


teriorand  to  the  inner  side  of  the  last  molar  tooth.  If,  in  operating  for  cleft  palate,  the 
tissues  are  loosened  from  the  bone  too  close  to  the  hamular  process,  this  artery  may  be 
torn  near  its  e.xit  from  the  foramen,  in  which  case  the  bleeding  is  very  free.  To  control 
it,  the  canal  can  be  plugged  with  a  slip  of  gauze.      In  detaching  the  soft  palate  from 


FlCr.  140. — Roof  of  the  mouth 


Posterior  or  descending 
palatine  artery 


Hamular  process 

Tensor  palati  muscle 
oved. 


the  posterior  edge  of  the  hard  palate,  it  should  be  remembered  that  this  attachment 
is  quite  strong.  Not  only  are  the  muscles  of  the  soft  palate  themselves  attached  to 
the  bone,  but  the  pharyngeal  aponeurosis  which  lies  under  the  mucous  membrane  on 
the  posterior  or  upper  surface  of  the  soft  palate  is  also  attached  to  the  bone. 

Palatal  Arches. — Farther  back  in  the  mouth,  one  sees  the  anterior  and  pos- 
terior arches  of  the  palate  or  pillars  of  the  fauces  with  the  tivula.     The  anterior 


THE    MOUTH    AND    THROAT. 


113 


pillar  runs  from  the  soft  palate  to  the  tongue  and  is  formed  by  the  palatoglossus 
muscle.  The  posterior  pillar  runs  from  the  soft  palate  downward  to  the  sides  of  the 
pharynx  and  is  formed  by  the  palatophaTjngeus  muscle.     In  front  of  these  arches  and 

^--^Phar>ii-geal  tonsil 


Fossa  of  Rosenmuller 
Eustachian  tube 

Supratonsillar  fossa 

Pterygomandibular  fold 
Plica  triangula 


-Lateral  view  of  the  faucial  tonsil  and  pharj-ngeal  region 


running  from  the  roof  of  the  mouth  opposite  the  posterior  edge  of  the  last  molar  tooth 
downward  to  the  posterior  edge  of  the  ah'eolar  process  of  the  lower  jaw  is  an  elevation 
of  the  mucous  membrane  which  shows  the  line  of  junction  of  the  hard  and  soft  palates. 


Diagram  illustrating  the  blood  supply  of  the  faucial  ton^l. 


Faucial    Tonsils. — Between  the  pillars  of  the  fauces  lie  thefajccial  to7isils. 
They  are  limited  above  by  the  sulcus,  called  \}n&  supratonsillar  fossa,  formed  by  the 
approximation  of  the  pillars  and  a  fold  of  mucous  membrane,  called  the  plica  trian- 
gularis (His),  running  downward  from  the  anterior  pillar  and  often  blending  with 
8 


114  APPLIED  -  ANATOMY. 

the  tonsil.  Below  they  extend  a  variable  distance,  necessitating  depression  of  the 
tongue  with  a  spatula  in  order  to  make  their  lower  hmit  accessible.  They  lie  about 
opposite  the  angles  of  the  jaw  on  the  superior  constrictor  muscle  with  the  bucco- 
pharyngeal fascia  outside  of  the  muscle.  A  knowledge  of  their  structure  is  essential 
to  the  proper  treatment  of  their  diseases.  The  tonsils  are  oval  in  shape  and  when 
normal  in  size  project  but  little  beyond  the  pillars  of  the  fauces.  They  are  about 
2. 5  cm.  long  by  i  cm.  wide  and  consist  of  about  a  dozen  recesses  or  crypts  formed 
by  the  folding  inward  of  the  mucous  membrane.  From  these  crypts  follicles  extend. 
The  walls  of  the  crypts  contain  adenoid  tissue  as  well  as  mucous  glands.  The  tonsil 
is  held  together  by  connective  tissue  which  is  continuous  with  its  capsule  and  the 
submucous  fibrous  tissue  of  the  pharyn.x.  On  this  account  while  an  enlarged  tonsil 
can  at  times  be  shelled  out  of  its  bed,  especially  its  upper  portion,  at  others  it  is 
necessary  to  dissect  or  cut  it  out  by  means  of  a  knife,  scissors,  or  tonsillotome. 

The  blood-vessels  supplying  the  tonsil  are  five  in  number.  They  are;  the 
ascending  pharyngeal  branch  of  the  external  carotid,  the  ascending  palatine  and 
tonsillar  branches  of  the  facial,  the  tonsillar  branch  of  the  dorsalis  linguiz^  and  the 


Fig.  T43. — Point  of  puncture  for  tonsillar  abscess  "  If  an  imafiinary  horizontal  line  is  drawn  across  the 
base  of  the  uvula,  and  another  vertically  along  the  anterior  f  aucial  pillar,  they  will  intersect  at  a  point  overlying 
the  supratonsillar  fossa.  Just  external  to  this  is  the  best  point  tor  opening  a  quinsy." — St.  Clair  Thomson,  M.D., 
Brit.  M.  J.,  March  25,  1905,  p.   645, 

descending  palatine  branch  of  the  internal  maxillary.  Ordinarily,  these  branches  are 
small,  but  sometimes  some  of  them  are  large  and  may  cause  troublesome  hemorrhage. 
In  inflammation  of  the  tonsils,  these  vessels  of  course  are  larger  than  usual. 

The  tonsils  are  subject  to  inflammation  and  tumors.  Tumors  are  rare;  they 
grow  inward  and  obstruct  breathing  and  swallowing.  Attempts  are  made  to  remove 
them  either  by  scraping,  cutting,  snaring,  or  burning  them  with  the  electrocautery 
from  the  mouth;  or  they  are  sometimes  removed  through  an  external  incision  through 
the  neck.  This  latter  is  a  very  severe  procedure  on  account  of  the  depth  of  the 
tonsil  and  the  number  of  important  structures  which  overlie  it. 

Tonsillitis  or  quinsy  is  an  inffammation  of  the  tonsils  which  leads  to  the  for- 
mation of  an  abscess.  In  mild  cases  the  crypts  or  lacunas  are  affected,  forming  a 
follicular  or  lacunar  tonsillitis.  In  this  form  epithelium  and  inflammatory  matter  are 
poured  into  the  follicles  and  distend  them,  often  showing  as  white  plugs  protruding 
from  the  mouth  of  the  crypt.  In  its  treatment,  in  addition  to  local  applications, 
surgeons  enlarge  the  openings  into  the  crypts  with  a  small  knife  and  scoop  the  con- 
tents out  with  a  sharp  spoon.  In  severe  cases,  the  whole  substance  of  the  tonsil 
and  even  the  connective  tissue  around  it  are  involved  in  the  inflammation,  forming 
2.  parenchymatous  tonsillitis.  It  frequently  proceeds  to  the  formation  of  pus.  When 
this  forms  in  the  substance  of  the  tonsil  it  may  break  into  a  follicle  and  discharge  into 
the  throat.      An  abscess  of  the  tonsil  may  become  quite  large,  bulging  toward  the 


THE   MOUTH    AND   THROAT. 


115 


median  line,  and  on  brealiing  ma_y  cause  suffocation  by  passage  of  the  pus  into  the 
larynx.  If,  as  is  usually  the  case,  the  pus  involves  the  tissue  around  the  tonsil,  form- 
ing a  peritonsillar  abscess,  it  pushes  upward  behind  the  anterior  pillar  into  the  supra- 
tonsillar  fossa  and  bulges  forward,  stretching  the  pillar  over  it.  To  evacuate  this  pus 
an  incision  should  be  made  directly  anteroposteriorly,  with  the  flat  side  of  the  blade 
parallel  with  the  edge  of  the  pillar,  or  a  slender  pair  of  haemostatic  forceps  may  be  used. 
A  centimetre  and  a  quarter  ( }4  in.  j  is  deep  enough  usually  to  plunge  the  knife;  the 
point  should  not  be  pointed  outwardly  but  directly  backward.  The  incision  should 
be  just  above  the  upper  and  lateral  edge  of  the  anterior  pillar  (Fig.  143).  Some 
small  vessels  may  bleed,  but  this  will  either  stop  spontaneously  or  may  be  controlled 
by  packing.  The  ascending  pharyngeal  artery  lies  beneath  the  tonsil.  The  tonsil 
lies  on  the  pharyngeal  aponeurosis  and  the  superior  constrictor  muscle,  while  the  as- 


Styloglossus 
Stylopharyngeus 

Stylohyoid 

Internal  carotid  artery 

Internal  jugular  vein 

Digastric 


?t —  Stemomastoid 


capitis  anticus  major 


Fig.  144. — Transverse  frozen  section  passing  through  the  faucial  tonsil  and  showing  its  relation  to  the  internal 

carotid  artery. 

cending  pharyngeal  artery  and  external  carotid  lie  outside  of  them,  so  that  both 
structures  would  have  to  be  cut  before  the  vessels  would  be  wounded.  The  internal 
carotid  artery  lies  still  deeper  (2  to  2.5  cm.)  behind  and  external  to  the  tonsil.  It  is 
usually  well  out  of  harm's  way  unless  dilated  (see  page  123,  Fig.  156),  but  the  pus  may 
burrow  into  it  and  cause  fatal  hemorrhage.  Sometimes  pus  may  burrow  through  the 
constrictor  muscle  and  enter  the  tissues  of  the  neck.  In  severe  tonsillitis  the  deep 
lymphatics  beneath  the  angle  of  the  jaw  become  enlarged. 

Hypcrtyophy  of  the  tonsils  is  common  and  is  treated  by  removing  them  entirely  or 
level  with  the  palatal  arches.  An  instrument  called  the  tonsillotome  is  used,  or  it 
is  done  vi'ith  a  knife  or  scissors  or  snare.  Fatal  bleeding  has  followed  this  oper- 
ation. The  blood  supply  to  the  tonsil  has  already  been  given.  If  the  bleeding  is  so 
free  as  to  threaten  the  life  of  a  patient,  the  external  carotid  artery  should  be  ligated 
as  all  the  vessels  supplying  the  tonsil  are  derived  from  it. 


ii6  APPLIED    AXATOMY. 

Enucleation  is  performed  by  grasping  the  tonsil  with  toothed  forceps,  drawing  it 
out,  and  cutting  it  loose  with  knife  or  scissors  from  its  attachments  to  the  pillars  and 
aponeurosis  beneath.  Sometimes  after  loosening  its  attachments  abo\-e  it  is  torn 
loose  or  shelled  out,  from  above  downward,  by  the  finger  or  a  blunt  instrument.  On 
account  of  the  capsule  sending  prolongations  into  the  tonsil,  it  cannot  readily  be 
' '  shelled  out ' "  and  portions  may  remain  and  require  to  be  remo\-ed  with  the  forceps 
and  scissors  or  tonsillar  punch.  It  is  a  disagreeable  and  bloody  procedure  and  is 
usually  done  under  a  general  anaesthetic. 

Retropharyngeal  abscess  may  arise  from  any  one  of  three  causes, — cer\'ical 
caries,  suppuration  of  lymphatic  nodes,  or  extension  of  pus  from  the  middle  ear 
through  the  canal  for  the  tensor  tympani  muscle.  The  pharyngeal  aponeurosis  lies 
under  the  mucous  membrane  and  between  it  and  the  constrictor  muscle.  It  is  thick 
aboye  and  fades  away  below.  It  fills  up  the  gap  aboye  between  the  superior  constric- 
tor and  the  base  of  the  skull  and  is  attached  to  the  pharyngeal  spine  on  the  under  surface 
of  the  basilar  process.  It  is  lined  with  the  mucous  membrane  and  covered  by  the 
constrictor  muscles.  0\er  all  is  the  bitccopharvngeal  fascia,  a  thin  laver  continu- 
ous forward  o\-er  the  buccinator  muscle  and  separated  from  the  prevertebral  fascia 


Fig-  145. — Cer\-ical  caries  \rith  retrophar\Tigeal  abscess  opening  just  posterior  to  the  stemomr.stoid  muscle. 

by  very  loose  connective  tissue.  The  space  between  these  two  layers  of  fascia 
is  known  as  the  rdropharyngeal  space  and  pus  can  follow  it  downward  behind  the 
pharyn.x  and  oesophagus  into  the  posterior  mediastinum.  Retropharyngeal  abscesses 
occur  beneath  the  pharyngeal  aponeurosis  and  bulge  into  the  throat.  On  account 
of  the  looseness  of  this  aponeurosis  and  its  lack  of  firm  attachments,  these  abscesses 
may  not  bulge  forward  as  a  distinct  circumscribed  swelling  as  abscesses  do  elsewhere, 
but  are  more  apt  to  gra^■itate  do-i\nward  and  hang  in  a  loose  bag-like  manner  opposite 
the  base  of  the  tongue.  They  are  not  easily  felt,  being  so  soft,  and  to  see  them  prop- 
erly the  tongue  should  be  held  down  with  a  tongue  depressor.  In  looking  for  their 
origin,  a  careful  examination  of  the  spine  should  be  made  to  detect  the  possible 
e.xistence  of  spinal  caries  or  Pott' s  disease,  and  the  ear  should  be  examined  for  suppur- 
ative otitis  media.  The  lymph-nodes,  which  sometimes  give  rise  to  these  abscesses, 
are  one  or  two  lying  on  the  anterior  surface  of  the  vertebral  column  between  it  and  the 
pharyngeal  aponeurosis  and  constrictor  muscles.  In  evacuating  these  abscesses  the 
safest  way  is  to  place  the  child  on  its  back  with  the  head  hanging,  the  pus  then  gra\i- 
tates  toward  the  roof  of  the  pharjmx.  The  tongue  is  held  out  of  the  way  with  a  tongue 
depressor  and  the  abscess  can  be  well  seen  and  incised.  If  the  flow  of  pus  is  free,  as 
soon  as  the  incision  is  made,  if  in  a  child,  the  feet  may  be  grasped  and  elevated,  the 
head  hanging  downward,  and  the  pus  will  flow  out  of  the  mouth. 


THE    MOUTH    AND    THROAT. 


117 


The  pus  may  not  only  point  in  the  mouth  but  can  work  its  way  laterally.  In 
such  a  case  it  may  pass  out  behind  the  sheath  of  the  great  vessels  and  make  its 
appearance,  as  I  have  seen  it,  behind  the  posterior  edge  of  the  sternomastoid  muscle. 
If  a  tumor  is  present  in  this  situation,  the  pus  may  be  evacuated  by  an  incision  at 
this  point  and  the  abscess  drained  there  instead  of  making  an  opening  through  the 
pharynx.      This,  of  course,  tends  to  guard  against  infection  from  the  mouth. 

Lingual  Nerve. — The  lingual  nerve  or  gustatory  branch  of  the  fifth  can  be 
readily  exposed  in  the  mouth.  On  looking  into  the  mouth,  a  fold  can  be  seen  going 
up  and  back  just  behind  the  last  molar  tooth.  This  is  formed  by  the pte7ygomandib- 
ii/ar  ligament,  running  from  the  tip  of  the  internal  pterygoid  plate  to  the  posterior 
extremity  of  the  mylohyoid  ridge  and  joining  the  buccinator  with  the  superior  con- 


Mandibular  (inferior 
dental)  artery 


Subma-xillary  gland 


146. — View  of  mandibular  and  lingual  nerves  from  within 


Stridor  muscles.      An  incision  made  just  internal  to  this  fold,  below  and  behind  the 
last  molar  tooth,  will  lead  one  down  to  the  lingual  nerve  close  to  the  bone. 

The  mandibular  nerve  is  also  reached  through  an  incision  running  from  the 
last  upper  to  the  last  lower  molar  tooth.  The  finger  is  introduced  and  the  spine  of 
Spix  felt  at  the  inferior  dental  foramen.  The  nerve  and  artery  enter  the  mandible  at 
this  point,  the  artery  being  below  and  posterior.  The  operation  of  Paravicini  on  this 
nerve  through  the  mouth  is  unsatisfactory  on  account  of  the  lack  of  proper  e.xposure. 
It  is  better  to  attack  the  nerve  from  the  outside  as  detailed  on  page  60. 


PHARYNX. 

The  pharynx  is  the  common  air  and  food  tract  that  lies  behind  the  nose,  mouth, 
and  laryn.x.  It  extends  from  the  base  of  the  skull  above  to  the  oesophagus  below. 
Its  lower  end  is  at  the  cricoid  cartilage,  which  is  opposite  the  sixth  cer\ical  vertebra. 
In  passing  an  instrument  directly  backward  through  the  nose,  one  strikes  the  base  of 
the  skull  or  interval  between  the  basilar  process  and  the  atlas.  In  looking  into  the 
throat  through  the  mouth,  one  is  level  with  the  body  of  the  second  vertebra.  If,  by 
means  of  a  hook,  the  soft  palate  is  raised  or  pushed  aside  and  the  head  tilted  slightly 
backward  one  sees  the  anterior  tubercle  of  the  atlas.      The  rounded  projection  can 


ii8 


APPLIED    ANATOMY. 


readily  be  felt.     The  pharyn.x  has  seven  openings  into  it,  viz. :  the  two  posterior  nares, 
the  two  Eustachian  tubes,  the  mouth,  the  laryn.x,  and  the  oesophagus. 

Posterior  Nares  or  Choanae. — These  can  readily  be  seen  by  means  of  the  rhino- 
scopic  mirror.  They  are  separated  by  the  posterior  edge  of  the  bony  septum,  the 
vomer  bone.  They  are  2.5  cm.  (  i  in.)  long  and  1.25  cm.  wide,  hence  are  of  sufiS- 
cient  size  to  allow  a  well  lubricated  little  finger  to  pass  into  them  from  the  anterior 
nares.  The  tip  of  an  index  finger  can  be  inserted  through  the  mouth  below,  hence 
the  entire  length  of  the  lower  meatus  of  the  nose  and  upper  surface  of  the  soft  palate 
can  be  palpated. 

Projecting  from  each  lateral  wall  toward  the  septum  are  the  rounded  posterior 
ends  of  the  middle  and  inferior  turbinated  bones.     Sometimes,  high  up,  the  posterior 
end  of  the  superior  turbinate  can  be  seen.      The  posterior  end  of  the  inferior  turbi-  ' 
nate  is  frequently  enlarged  by  a  swelling  of  its  membrane,  forming  a  posterioi'  turbi- 


—  First  cervical  vertebra 


Lingual  tonsil 

Anterior  pillar 


Faucial  tonsil' 

Posterior  pill 


//    ^^ Second  cervical  vertebra 


Third  cervical  vertebra 


Cricoid  cartilage 
Trachea 


•Fifth  cervical  vertebra 

Arytenoid  cartilage 

■Sixth  cervital  vertebra 

■CEsophagus 

.Cricoid  cartilage 

.Seventh  cervical  vertebra 


Fig.  147. — Lateral  ■ 


of  pharynx  and  larynx. 


nate  hypertrophy.  Not  only  does  the  mucous  membrane  of  the  inferior  turbinate 
bones  become  enlarged,  but  that  on  the  septum  likewise.  This  constitutes  hypertrophy 
or  thickening  of  the  septum.  A  polypus  may  project  from  the  nasal  cavities  back- 
ward into  the  throat.  I  removed  a  very  large  one  by  pushing  it  with  the  finger  into 
the  pharynx  and  then  dragging  it  out  of  the  mouth. 

The  posterior  nares  are  quite  a  distance  anterior  to  the  edge  of  the  soft  palate, 
hence  it  is  extremely  difiicult  to  make  applications  by  way  of  the  mouth.  A  much 
easier  way  is  to  make  them  through  a  tube  introduced  into  the  nose,  or  even,  as 
when  the   electrocautery  is  used,   without  a  protecting  tube. 

Eustachian  Tube. — On  each  side,  at  a  point  about  opposite  the  inferior  turbi- 
nals,  are  the  orifices  of  the  Eustachian  tribes  with  the  fossa  of  Rosenmiiller  above. 
The' Eustachian  tube  runs  from  the  upper  portion  of  the  pharynx  to  the  middle 
ear,  opening  just  behind  the  tympanic  membrane,  on  the  anterior  wall.      It  is  about 


THE   MOUTH    AND   THROAT. 


119 


4  cm.  long,  2.5  cm.  being  cartilaginous  (pharyngeal  portion)  and  1.5  cm.  being 
bony.  At  the  junction  of  the  bony  and  cartilaginous  portions  the  lumen  is  slightly 
diminished,  forming  the  isthmus.     The  tube  runs  upward,  backward,  and  outward. 

The  mucous  membrane  of  the  throat  is  continuous  with  that  lining  the  tube  and 
tympanum,  therefore  inflammation  of  the  pharynx  travels  up  the  tube  and  affects  the 
middle  ear.      This  is  the  manner  in  which  earache  or  inflammation  and  suppuration 


Fig.  T48 — Rhinoscopic  mirror  in  position.    A  view 
can  be  obtained  of  ttie  vault  of  the  piiarynx  and  poste- 


Fio.  149- 


-Palpation  of  the  posterior  nares  and  pha 
yngeal  tonsil. 


of  the  middle  ear  is  produced.  This  also  explains  why  impairment  of  hearing  so 
often  accompanies  or  follows  sore  throat.  When  the  tube  is  in  a  healthy  condition, 
the  air  finds  free  access  to  the  ear,  in  swallowing,  sneezing,  etc.  This  is  readily 
demonstrated  by  closing  the  nostrils  and  swallowing,  when  the  pressure  of  air  out- 
side the  ear  drum  will  be  distinctly  felt.     When  inflammation  affects  the  lining  mem- 

^^^Vault  of  pharynx 

^/Superior  turbinate 


-Septum 

Middle  turbinate 

Mouth  of  Eustachian  tube 

-^Inferior  turbinate 


-View  of  posterior  i 


I  the  pharyngeal  mirror. 


brane  it  swells  and  blocks  up  the  tube  and  prevents  the  free  access  of  air  to  the  ear. 
If  the  swelling  is  not  too  great,  air  can  be  forced  from  the  throat  to  the  ear  by  three 
different  means.  The  distention  of  the  middle  ear  by  air  is  called  inflating  it.  The 
method  of  Valsalva  consists  in  holding  the  nostrils  and  mouth  shut  and  blowing. 
If  the  air  enters  the  middle  ear,  the  tympanic  membranes  will  be  felt  to  bulge 
outward.      The  method  of  Politzer  is  to  have  the  patient  hold  a  small  quantity  of 


I20  APPLIED    ANATOMY. 

water  in  the  mouth.  The  nozzle  of  a  rubber  bag  is  introduced  into  one  nostril, 
closing  both  nostrils  with  the  fingers  and  thumb  of  the  unengaged  hand.  On  telling 
the  patient  to  swallow,  the  bag  is  compressed  and  the  air  enters  the  Eustachian  tube. 
As  the  patient  swallows,  the  tensor  palati  muscle  opens  the  mouth  of  the  tube  and 
as  the  bag  is  compressed  the  air  rushes  up  the  tube.  Sorhetimes  the  vapors  of  ether, 
chloroform,  etc. ,  are  used.     The  third  method  is  by  the  Eustachian  catheter. 

The  Eustachian  catheter  is  a  small,  hard  rubber  or  silver  tube,  slightly  bent 
at  the  extremity  and  long  enough  to  reach  from  the  anterior  nares  in  front  to  the 
posterior  wall  of  the  pharynx.      The  end  of  the  catheter  having  been  inserted  into 


Fig.  151. — Anteroposterior 


nd  the  relation  of  tlie  various 


the  mouth  of  the  Eustachian  tube,  air  is  blown  in  with  the  Politzer  air-bag.  By 
means  of  a  rubber  tube  going  from  the  patient's  ear  to  the  surgeon's  ear,  the  air  can 
be  heard  entering  the  middle  ear. 

Inh'oditcing  the  Eustachian  Catheter. — In  introducing  the  Eustachian  catheter, 
the  tip  of  the  nose  is  to  be  tilted  upward  until  the  anterior  nares  are  raised  to  the 
level  of  the  floor  of  the  nose.  The  tip  of  the  catheter  is  then  passed  first  upward 
(Fig.  152),  then  along  the  floor  until  it  is  felt  to  pa.ss  beyond  the  soft  palate  and  strike 
the  posterior  wall  of  the  pharynx  (Fig.  153).      It  is  usually  advised  to  enter  the 


THE    MOUTH    AND    THROAT. 


catheter  in  a  vertical  position  and  then  change  to  a  horizontal  one  as  soon  as  the  beak 
passes  over  the  elevation  which  marks  the  separation  of  the  vestibule  of  the  nose  from 
the  interior.  If  this  method  is  used,  care  should  be  taken  to  keep  the  tip  of  the  catheter 
on  the  floor  of  the  nose  and  not  pass  it  up  in  the  region  of  the  middle  turbinate  bone. 

There  are  three  ways  of  introducing  the  beak  of  the  catheter  into  the  mouth  of 
the  tube  after  it  is  felt  touching  the  posterior  pharyngeal  wall.  The  first  is  to  with- 
draw the  beak  about  2  cm.  away  from  the 
wall  of  the  pharyn.x  and  then  turn  it  upward 
and  outward,  pushing  it  a  tritfe  onward. 
The  second  way  is  to  turn  the  beak  directly 
outward  and  draw  it  forward,  when  it  can 
be  felt  passing  over  the  cartilaginous  open- 
ing of  the  tube.  The  third  way  is  to  turn 
the  beak  inward  and  draw  it  forward  until 
it  catches  behind  the  septum.  This  is  op- 
posite the  anterior  edge  of  the  mouth  of 
the  tube.  The  beak  is  then  rotated  down- 
ward and  then  upward  and  outward  into 
the  tube. 

Liquids  and  sprays  are  sometimes  in- 
jected into  the  ear  through  the  catheter; 
bougies  are  also  passed  into  the  tube  in  the 
same  manner  as  the  catheter  or,  if  flexible 
bougies  are  used,  they  are  passed  through 
the  catheter.  As  the  tip  of  the  bougie 
passes  into  the  bony  portion  of  the  canal, 
the  constriction  of  the  isthmus  can  be  felt 
2.5  cm.  up  from  its  mouth.  The  bougie 
should  not  be  passed  farther  than  3  cm. 
into  the  tube,  otherwise,  if  the  tympanum  is  entered,  the  ossicles  are  apt  to  be  injured. 

Openings  of  the  Mouth,  Larynx,  and  CEsophagus. — The  opening  of  the 
mouth  into  the  pharynx  is  sometimes  narrowed  from  cicatricial  contractions,  resulting 


atheter,  first 


Introducing  the 

third  step. 

from  ulcerative  processes  due  to  syphilis,  caustics,  etc.  There  is  rarely  obstruction 
downward,  so  that  these  patients  can  usually  swallow,  but  the  cicatrices  contract  the 
opening  upward,  and  the  soft  palate,  its  arches,  and  the  walls  of  the  pharynx  may  be 
all  bound  together  in  one  cicatricial  mass,  preventing,  as  I  have  seen,  all  respiration 
through  the  nose.  This  condition  is  an  exceedingly  difficult  one  to  remedy,  as  the 
contraction  tends  to  recur  even  after  the  most  radical  operations. 

The  opening  into  the  larynx  is   more  accessible  than  is  often  supposed.      On 
drawing  the  tongue  well  forward,  the  tip  of  the  epiglottis  can  be  seen.      If  a  long 


APPLIED    ANATOMY. 


straight  tongue  depressor  is  used,  Kirstein  has  shown  that  in  many  patients  the 
arytenoid  cartilages  and  even  a  portion  of  the  vocal  cords  can  be  seen.  The  open- 
ing into  the  larynx  can  readily  be  felt  by  a  finger  introduced  into  the  mouth.  In  cases 
of  suffocation  from  a  foreign  body,  as  a  piece  of  meat,  it  is  usually  lodged  at  this 
point,  part  of  the  foreign  body  being  in  the  larynx  and  part  in  the  pharynx.  It  can 
readily  be  dislodged  by  the  finger,  as  I  have  done  in  impaction  of  meat,  the  result  of 
vomiting  in  ether  narcosis.  The  forefinger  should  be  thrust  its  full  length  into  the 
mouth  and  throat  and  swept  from  side  to  side.  The  obstructing  body  can  usually 
be  brushed  aside  and  brought  up  in  front  of  the  finger  into  the  mouth. 

The  opening  of  the  oesophagus  is  in  a  line  with  the  long  axis  of  the  pharynx;  it 
is  at  its  lower  end.  The  opening  of  the  larynx,  on  the  contrary,  is  more  on  its 
anterior  wall.  It  is  for  this  reason  that  when  an  oesophageal  tube  is  introduced,  either 
through  the  mouth  or  through  the  nose,  it  goes  down  into  the  oesophagus  and  does 
not  enter  the  larynx.      The  oesophagus  is  narrowest  at  this  point. 

The  pharyngeal  tonsil  stretches  across  the  posterior  wall  and  roof  of  the 
pharynx  from  the  opening  of  one  Eustachian  tube  to  that  of  the  other.      It  is  also 

'Pharyngeal  tonsil 


Eustachian  tube 

^Supratonsillar  tossa 

"Pterygomandibular  fold 
-Plica  triangularis 

.Anterior  pillar 
"■Faucial  tonsil 
Posterior  pillar 


Lateral  view  of  the  pharyngeal  region. 


known  as  Luschka  s  tonsil.  It  is  composed  of  lymphoid  tissue,  and  when  enlarged 
constitutes  the  disease  known  as  adenoids.  It  is  not  true  secreting  gland  tissue, 
though  it  contains  some  mucous  glands.  It  hangs  from  the  vault  of  the  pharynx  in  a 
more  or  less  lobulated  mass  and  when  large,  in  children,  obstructs  nasal  respira- 
tion. Mouth-breathing  results,  the  child  is  apt  to  snore  and  make  queer  sounds 
when  sleeping,  and  the  habit  of  keeping  the  mouth  open  causes  a  peculiar  expres- 
sion of  the  face  almost  pathognomonic  of  the  affection.  The  blood  supply  at  times 
is  abundant.  When  adenoids  are  present,  their  removal  is  usually  undertaken. 
This  is  done  by  introducing  an  instrument  either  through  the  nose  or  through  the 
mouth  and  scraping  them  off.  A  curette  is  used  for  this  purpose.  That  known  as 
Gottstein's  consists  of  an  oval-shaped  ring  set  at  right  angles  to  a  long  shaft.  It  is 
introduced  through  the  mouth  and  up  behind  the  soft  palate.  It  is  then  pushed 
against  the  vault  of  the  pharynx  and  posterior  wall  and  drawn  downward  cutting 
and  scraping  the  adenoid  tissue  away.  A  much  smaller  ring  curette  set  on  a  long, 
delicate,  but  stiff  handle  may  be  used  through  the  nose  for  the  same  purpose.  In  using 
the  latter  instrument,  it  is  common  to  use  an  anesthetic  and  operate  with  the  head 
in  a  hanging  position.  Free  bleeding  may  occur  from  this  operation.  To  control  it, 
injections  of  ice  water  or  a  strong  alum  solution  may  be  tried  or  gauze  may  be 
packed  behind  the  soft  palate  or  pushed  in  from  the  anterior  nares.     A  folded  pad  of 


THE    MOUTH    AND    THROAT. 


123 


gauze  may  be  attached  to  the  thread  of  a  Bellocq  cannula  and  the  pad  introduced 
as  is  done  in  plugging  the  posterior  nares.  A  curved  forceps  with  cutting  blades 
is  also  used  to  remo\-e  this  growth. 

Fossa  of  Rosenmiiller. — This  is  the  depression  above  and  behind  the  open- 
ings of  the  Eustachian  tubes.  The  walls  of  the  pharynx  are  weakest  at  this  point 
owing  to  the  superior  constrictor  muscle  not  coming  so  high  up.  Hernia  of  the 
mucous  membrane  sometimes  occurs  here.  When  the  beak  of  the  Eustachian  cath- 
eter fails  to  enter  the  mouth  of  the  tube  it  usually  enters  this  fossa. 

The  internal  carotid  artery  runs  up  the  neck  outside  of  the  pharyn.x  and 
opposite  the  space  between  the  posterior  arches  of  the  palate  and  the  posterior  wall 
of  the  pharynx.  It  is  from  i  to  2  cm.  behind  and  to  the  outer  side  of  the  tonsils. 
It  is  separated  from  the  cavity  of  the  throat  by  its  own  proper  sheath,  by  the  thin 
buccopharyngeal  fascia  covering  the  constrictor  muscles,  by  the  constrictor  muscles, 
the  pharyngeal  aponeurosis,  and  the  mucous  membrane.  As  the  tonsils  lie  between 
the  pillars  of  the  fauces,  in  opening  a  tonsillar  abscess  the  knife  is  not  carried  either 


Fig.  156. — Transverse  dissection  of  the  i 
exposed.    The  internal  carotids  are  see 


;ck.    The  posterior  wall  of  the  pharynx  has  been  removed  and  the  vessels 
I  to  be  abnormally  tortuous,  with  a  tendency  to  bulge  into  the  pharynx. 


behind  or  through  the  posterior  pillar  of  the  fauces.  It  is  practically  impossible  to 
wound  a  normal  internal  carotid  artery.  In  old  people  the  internal  carotid  sometimes 
becomes  lengthened  and  tortuous  in  the  same  manner  as  do  the  temporal  arteries.  In 
such  cases  the  artery  may  form  a  pulsating  swelling  behind  and  projecting  farther 
inward  than  the  edge  of  the  posterior  pillar.  This  I  have  once  seen.  It  may  be 
mistaken  for  a  true  aneurism,  as  it  pulsates  and  the  pulsation  is  readily  stopped  by 
pressure  on  the  common  carotid  on  the  outside  of  the  neck.  If,  however,  the  possi- 
bility of  this  condition  is  borne  in  mind,  the  diagnosis  can  readily  be  made.  The 
pulsating  swelling  can  readily  be  seen  and  felt  with  the  finger  just  behind  the  posterior 
pillar  of  the  fauces. 

The  mucous  membrane  of  the  nasopharynx  is  ciliated  columnar;  that  of  the 
lower  portion  is  squamous.  It  contains  racemose  mucous  glands  and  follicles  or  crypts 
surrounded  by  lymphoid  tissue.  It  is  well  supplied  with  blood-vessels.  It  is  fre- 
quently affected  by  inflammation  or  pharyngitis.  When  the  follicles  are  markedly 
involved  they  can  be  seen  studded  over  the  posterior  wall  of  the  pharynx.  This 
constitutes  a  follicular  pharyngitis.  Not  infrequently  some  ulceration  may  be 
present,  forming  an  ulcerative  pharyngitis.  Infection  attacks  it,  as  in  diphtheritic 
pharyngitis.  Should  pus  or  pharyngeal  abscess  form  around  the  pharynx,  arising 
from  an  infection  from  the  oral  cavity,  the  pus  occupies  the  retropharyngeal  space 


124  APPLIED    AXATOilY. 

between  the  buccopharyngeal  fascia  and  prevertebral  fascia.  Its  spread  upward  is 
limited  by  the  skull;  laterally  it  is  limited  by  the  sheath  of  the  carotid  vessels;  hence 
it  passes  downward  behind  the  oesophagus  and  may  enter  the  posterior  mediastinum. 
Foreign  bodies  may  become  lodged  at  the  lower  end  of  the  pharynx  and  at  the 
beginning  of  the  cesophagus.  As  this  is  about  15  cm.  (6  in.)  from  the  teeth,  it  is 
beyond  the  reach  of  the  hnger.  Luckily,  this  is  below  the  opening  of  the  larynx  and 
the  need  for  immediate  relief  is  not  so  urgent. 

THE    LARYNX. 

The  larynx  extends  from  the  top  of  the  epiglottis  to  the  lower  edge  of  the 
cricoid  cartilage.  It  is  composed  of  the  three  large  cartilages — epiglottis,  thyroid,  - 
and  cricoid — and  three  pairs  of  small  ones — the  arytenoids,  the  cornicida;  laiyngis 
or  caiiilages  of  Santorini,  and  the  cuneiform  or  cartilages  of  JVrisderg. 

The  position  of  the  larynx  in  relation  to  the  spine  varies  according  to  age.      In 
the  infant  it  lies  opposite  the  second,  third,  and  fourth  cer\-ical  vertebrse;  in  the  adult 


Epiglottis 


Greater  horn  of  hyoid  bone 


Body  of  hyoid  bone 

Superior  comu 

Opening  for  superior  laryngeal 


ThiTohyoid  membrane 
Thyroid  cartilage 


Inferior  comu 
Cricothyroid  membrane 
Cricoid  cartilage 

Trachea 


FlG.  157. — Anterior  view  of  hyoid  bone  and  larynx. 

it  lies  opposite  the  fourth,  fifth,  and  sixth.  The  larynx  being  loosely  attached  varies 
in  relation  to  the  vertebrse  according  to  the  position  of  the  head,  so  that  the  anterior 
portion  of  the  cricoid  cartilage  ma)'  be  opposite  the  seventh  cervical  \-ertebra  in  some 
positions. 

Epiglottis. — LTsually  the  tip  of  the  epiglottis  lies  lower  than  the  dorsum  of  the 
tongue,  so  that  looking  into  the  mouth  it  is  not  seen;  it  may,  however,  be  brought 
into  view  by  depressing  the  base  of  the  tongue  and  drawing  it  forward  with  a  long 
tongue  depressor.  As  the  epiglottis  rises  above  the  level  of  the  hyoid  bone,  a  cut- 
throat wound  passing  above  that  bone  may  cut  its  tip  entirely  off.  In  \-iewing  the 
epiglottis  from  above  downward  it  is  seen  to  project  somewhat  backward  in  its  middle. 
This  is  visible  in  the  laryngoscopic  mirror  and  is  called  the  cushion  of  the  epiglottis. 

Running  forward  from  the  epiglottis  to  the  base  and  the  sides  of  the  tongue  are 
three  folds  of  mucous  membrane,  one  median  and  two  lateral,  called  the  glosso- 
epiglottic  folds.  These  form  four  fossae;  those  on  each  side  of  the  median  line  are 
called  the  valleciilce.  In  these  fossae  foreign  bodies,  such  as  fish-bones,  etc. ,  may 
become  lodged.      They  are  readily  seen  by  the  laryngoscopic  mirror. 


THE    MOUTH    AND   THROAT. 


125 


The  thyrohyoid  membrane  passes  between  the  hyoid  bone  above  and  the 
thyroid  cartilage  below  ;  crossing  it  is  the  hyoid  branch  of  the  superior  thyroid  artery. 
It  is  a  quite  small  vessel,  of  little  clinical  importance,  and  ordinarily  does  not  reach 
the  median  line. 

The  posterior  edge  of  this  membrane,  running  from  the  superior  corner  of  the 
thyroid  cartilage  to  the  hyoid  bone,  is  called  the  thyrohyoid  ligament.  This  liga- 
ment has  a  small  cartilaginous  nodule  in  it,  the  cartilago  triticea.  Piercing  the 
membrane  on  its  side  are  the  internal  branches  of  the  superior  laryngeal  nerve 
and  the  superior  laryngeal  vessels.  The  external  branch  of  the  superior  laryngeal 
nerve  supplies  the  cricothyroid  muscle,  while  the  internal  is  the  ner\e  of  sensation 
of  the  larynx. 

Pharyngotomy. — Sometimes,  in  order  to  remove  foreign  bodies  in  the  larynx  or 
oesophagus,  an  opening  is  made  through  the  membrane  between  the  hyoid  bone  and 
thyroid  cartilage. 

Thyroid  Cartilage. — This  is  the  largest  cartilage  of  the  laryn.x  and  contains 
the  vocal  cords.     They  lie  immediately  behind  or  just  below   the  most  prominent 


Body  of  hyoid  bone 
Thyrohyoid  membrane- 


Thyroid  cartilage. 


Cricoth^Toid  membrane 
Cricoid  cartilage 


Cartilago  triticea 


Inferior  comu 


Fig.  158. — Side 


r  of  hyoid  bone  and  larynx. 


portion  of  its  anterior  edge,  commonly  called  "Adam's  apple."  Since  the  cartilage 
is  large  and  strong  and  as  age  advances  tends  to  calcify,  cut-throat  wounds,  while 
opening  the  cavity  within,  do  not  often  pass  entirely  through  the  cartilage.  This 
cartilage  may  be  fractured  by  violence.  This  is  often  fatal  on  account  of  the  blood 
flowing  into  the  trachea  and  lungs  below  or  on  account  of  cedema  of  the  lining  mucous 
membrane  causing  obstruction  of  the  breathing.  Thyrotomy  or  division  of  the 
thyroid  cartilage  in  the  median  line  is  sometimes  done  to  remove  foreign  bodies  or 
new  growths.  In  these  cases  the  voice  will  be  hkely  to  be  impaired  by  the  interference 
with  the  vocal  cords. 

Cricothyroid  Membrane. — The  space  between  the  cricoid  and  thyroid  carti- 
lages is  small.  This  is  due  to  the  increase  in  width  of  the  cricoid  as  it  proceeds  back- 
ward. The  space  is  readily  felt  on  the  living  subject  between  the  thyroid  above  and 
the  cricoid  beneath  ;  the  membrane  passes  between  them.  It  is  crossed  by  a  small 
branch  of  the  superior  thyroid  artery,  the  cricothyroid.  It  is  not  large  enough  to  cause 
serious  trouble.      Introducing  a  tube  through  this  membrane  constitutes  the  operation 


126  APPLIED    ANATOMY. 

of  laryngotomy.  This  operation  is  but  seldom  performed.  The  space  is  too  small 
in  many  cases,  the  opening  is  not  made  sufficiently  low  and  it  is  too  close  to  the 
vocal  cords.  It  is  an  operation  of  emergenc}^  It  is  much  easier  to  make  a 
quick  opening  at  this  point  than  it  is  in  the  trachea  below,  as  it  is  more  superficial 
and  is  held  steady  in  place  by  the  cartilage  abo^'e  and  belo^v  it.  Even  in  adults  the 
space  is  sometimes  too  small  to  introduce  a  tube  without  force  and  the  operation 
should  never  be  done  below  the  age  of  thirteen.  On  account  of  the  membrane  being 
nearer  the  surface  than  is  the  trachea,  a  shorter  tube  should  be  used.  Before  intro- 
ducing the  tube,  care  must  be  taken  that  the  mucous  membrane  has  been  thoroughly 
divided,  as  othenvise  the  tube  will  push  it  before  it  and  slip  between  the  mucous 
membrane  and  the  cartilage  and,  therefore,  not  enter  the  cavity  of  the  larny.x. 

Cricoid  Cartilage. — This  is  much  larger  posteriorly  than  anteriorly  and  tills 
the  space  between  the  posterior  edges  of  the  thyroid  cartilage.  Its  outside  diamefer 
is  larger  than  that  of  the  trachea,  hence  it  can  readily  be  felt  and  forms  one  of  the 
most  important  landmarks  on  the  front  of  the  neck.      It  is  about  opposite  the  sixth 


;  the  interior  of  the  iaxyn.K  by  means  of  the  laryngoscopic  mirror. 

cervical  vertebra.  It  is  thick  and  strong  and  forms  a  complete  circle,  being  unlike 
the  tracheal  rings  in  this  respect.      It  is  rare  that  it  is  divided  in  operations. 

For  the  parts  concerned  in  tracheotomy  see  the  section  on  the  neck. 

Laryngoscopy. — The  interior  of  the  laryn.x  is  examined  by  means  of  a  small 
mirror,  i  to  3  cm.  in  diameter,  introduced  through  the  mouth  and  placed  just  below 
the  uvula  at  an  angle  of  a  little  more  than  45  degrees.  The  opening  of  the  larynx  is 
not  directly  beneath  the  mirror  but  slightly  anterior.  The  base  of  the  tongue  and 
lingual  tonsils,  the  glosso-epiglottic  folds  and  pouches,  and  the  epiglottis  can  be  seen 
in  front.  Posteriorlv  one  sees  the  two  arytenoid  cartilages  capped  with  the  cartilages 
of  Santorini.  Between  the  arytenoids  is  the  commissure  or  interarytenoid  space. 
To  the  front  and  outer  side  of  the  tip  of  the  arytenoid  cartilages  is  the  cartilage  of 
Wrisberg,  and  running  from  it  forward  are  the  arycpiglottic  folds.  To  the  outer 
side  of  the  aryepiglottic  fold  is  the  depression  called  the  sinus  pyi'iformis.  It  is  here 
that  congenital  cervical  iistulse  sometimes  open.  Near  the  middle  are  seen  the  two, 
white,  true  vocal  cords,  and  to  the  outer  edge  of  these  are  seen  the  false  vocal 
cords.  Between  these  two  is  the  opening  of  the  ventricle  of  the  laryn.x.  The  rings 
of  the  trachea  can  readily  be  seen  and  not  infrequently  even  the  point  of  bifurcation 
of  the  trachea  opposite  about  the  second  rib. 


THE    NECK. 


127 


Diseases  of  the  Larynx. — Syphilis  affects  the  larynx  and  produces  ulcers. 
These  may  involve  almost  any  portion  but  usually  they  are  anterior,  involving  the 
epiglottis.  They  are  often  associated  with  syphilitic  manifestations  in  the  mouth. 
Tuberculosis  affects  the  posterior  portion  of  the  larynx  and  the  bulb-like  swellings  of 
the  arytenoids  are  almost  pathognomonic.  Ulcers  when  they  occur  are  most  marked 
posteriorly.  This  affection  is  associated  with  a  blanching  of  the  mucous  membrane 
of  the  mouth  and  the  presence  of  a  white  frothy  mucus,  which  will  lead  the  laryn- 
gologist  to  suspect  the  existence  of  the  disease  before  a  view  of  the  larynx  is  obtained. 

Laryngitis  of  a  simple  nature  produces  a  reddening  of  the  cords  and  a  swelling 
of  the  membrane  generally. 

In  cedema  of  the  larynx,  the  serous  effusion  puffs  up  the  loose  mucous  membrane, 
particularly  of  the  aryepiglottic  folds  and  epiglottis. 

Tumors  both  benign  and  malignant  affect  the  larynx  and  can  at  times  be  seen  to 
arise  from  the  vocal  cords. 

Paralysis  of  the  muscles  is  most  frequent  from  interference  with  the  recurrent 


Plica  vocalis  (true  vocal  cord) 


^^w^- 

- 

Tuberculuir 
|^^^lsbe^g) 

1  cuneiform  i 

^  -"nmm^^^m"'  ^ 

^ 

TuberculuTT 
(Santorini) 

1  corniculatum 

of  the  larynx  as  seen  in  the  li 

aryngeal 

mirror. 

laryngeal  nerve.  This  nerve  supplies  the  abductor  muscles  and  when  paralyzed  the 
cords  tend  to  fall  together.  The  nerve  may  be  injured  in  operations  on  the  neck  or 
involved  in  cancer  of  the  thyroid  gland,  or  CESophagus,  or  in  aneurisms.  If  one  cord 
is  paralyzed,  the  voice  is  lost  temporarily,  and  when  it  returns,  it  is  changed  in  char- 
acter. Paralysis  of  both  nerves  does  not  cause  entire  loss  of  voice  because  the  cords 
fall  together,  but  may  induce  suffocative  symptoms  ending  in  death. 


THE   NECK. 

The  neck  supports  the  head.  It  is  a  pedestal  for  the  head,  and  is  long  in  pro- 
portion to  its  thickness;  the  apparent  object  of  this  being  to  elevate  the  head  and 
allow  it  to  be  moved  freely  in  different  directions.  The  animal  is  thus  better  enabled 
to  discover  its  enemies  and  to  guard  itself  against  them. 

The  various  structures  of  the  neck  are  mostly  long,  running  between  the  head 
above  and  the  trunk  below.  This  is  the  case  with  the  spine,  the  air-  and  food-pas- 
sages, the  blood-vessels,  nerves,  and  even  some  muscles,  as  the  sternomastoid  and 
trapezius.  The  shorter  structures  are  either  the  component  parts  of  the  longer 
ones,  as  the  vertebrae  of  the  spine  and  the  rings  of  the  trachea,  or  are  separate 
organs  like  the  larynx,  thyroid,  and  submaxillary  glands.  The  presence  of  these 
latter  organs  is  not  dependent  on  the  length  of  the  neck  as  is  that  of  the  others.  In 
the  frog,  which  practically  has  no  neck,  the  head  being  placed  directly  on  the  trunk, 
there  still  e.xist  both  larynx  and  thyroid  gland.  In  the  singing  birds  the  vocal 
organ  or  syrin.x  is  placed  in  the  chest  at  the  bifurcation  of  the  trachea.  As  regards 
the  cervical  spine,  blood-vessels,  air-  and  food-passages,  and  muscles,  these  evidently 
are  proportionate  to  the  length  of  the  neck.  In  the  batrachians  or  frogs  there  is  but 
a  single  cervical  vertebra;  in  the  swan  there  are  twenty-five  cervical  vertebrae,  and  in 
the  fishes  none.     In  man  of  course  the  number  of  cervical  vertebrae  remains  the  same. 


128  APPLIED    ANATOMY. 

seven,  no  matter  what  the  length  of  the  neck.  From  a  consideration  of  these  facts 
we  maj-  perhaps  state  that  the  neck  itself  is  a  subsidiary  organ,  not  of  any  great  im- 
portance in  itself,  but  rather  in  relation  to  some  other  portion  of  the  body — that 
portion  being  the  head.  It  is  the  staff  which  supports  the  head  by  means  of  the 
cervical  spine  and  muscles. 

The  neck  contains  the  great  currents  of  blood  which  pass  to  and  fro  between 
the  head  and  trunk.  It  carries  the  air-  and  food-passages,  \\-hich  run  from  the  mouth 
above  to  the  lungs  and  stomach  below,  and  incidentally  it  contains  the  lan,'nx,  the 
thyroid  and  subma.xillary  glands,  and  some  lymphatic  nodes.  The  cerebrospinal 
ner\'es  of  all  the  body  below  the  head  pass  either  into  the  neck  or  through  it  to  the 
parts  bevond.  From  these  facts  it  becomes  evident  that,  while  the  neck  in  itself  may 
be  a  subsidiary  organ,  for  our  purposes  it  is  of  the  greatest  importance,  because 
interference  with  its  structure  either  by  disease  or  injury  —  operati^"e  or  accidental' — 
ma^•  destroy  the  brain  above,  by  interfering  with  its  nourishment,  or  the  body  below, 
by  interfering  with  the  vital  functions  of  respiration  and  nutrition,  or  may  paralyze  it 
by  destroying  the  conductivity  of  its  ner\'es.  The  construction  of  the  neck  then 
should  be  studied  with  a  view  of  explaining  or  understanding  the  diseases  and  injuries 
of  its  various  parts  and  the  operations  performed  for  their  relief. 

Injuries  and  Diseases  of  the  Neck. — Owing  to  its  exposed  position  the 
neck  is  frequently  injured  by  sprains,  contusions,  cuts,  and  punctured,  gunshot,  and 
all  sorts  of  wounds.  The  cer\dcal  spine  may  become  dislocated  or  fractured  and  is 
frequently  the  seat  of  caries.  The  muscles  become  contracted,  producing  torticollis 
or  wrv-neck.      Thev  mav  sometimes  be  ruptured,  as  in  childbirth. 

The  arteries  are  affected  •\\ith  aneurism,  necessitating  their  ligation.  They  are 
also  divided  in  cut-throat  cases  and  wounds.  The  veins  are  of  importance  in  almost 
ever\'  operation;  bleeding  from  them  is  dangerous  and  may  be  difficult  to  control. 

The  lymphatic  nodes  are  more  numerous  than  elsewhere  in  the  body.  Frequently 
they  are  the  seat  of  tuberculous  or  sarcomatous  enlargement,  necessitating  their  re- 
moval. The^•  may  break  down  and  produce  wide-spreading  and  dangerous  abscesses, 
which  are  guided  in  their  course  by  the  fascias  ;  hence  a  knowledge  of  the  construc- 
tion of  the  deep  fascias  of  the  neck  enables  us  to  understand  them. 

The  submaxillary  and  tkyi-oid  glands  are  the  seat  of  enlargement  and  foreign 
growths  requiring  the  performance  of  e.xtensive  operations  for  their  e.xtirpation. 
Enlargement  of  the  thyroid  gland  constitutes  the  disease  known  as  goitre.  It  is  also 
invoh'ed  in  exophthalmic  goitre  or  Graves' s  or  Basedoic'  s  disease. 

The  skin  and  subcutaneous  tissue  become  the  seat  of  inflammation  and  cellulitis. 
In  cases  of  wounds  this  cellular  inflammation  may  involve  the  structures  beneath  the 
deep  fascia;  this  occurs  in  cut-throat  and  gunshot  wounds. 

The  neck  is  also  liable  to  other  affections,  such  as  cysts  due  to  embryological 
defects.  Large  cysts  are  formed  called  hvgromas,  also  sinuses  or  fistulee,  the  con- 
genital jistulcB  of  the  neck.  The  larynx  may  be  the  seat  of  malignant  disease;  hence 
its  remo\-al  is  undertaken.  The  operations  of  tracheotomy,  laryngotomy ,  and  cesoph- 
agotomv  are  also  at  times  necessarv.  In  order  to  understand  these  -various  affec- 
tions and  procedures  one  must  be  familiar  with  the  construction  of  the  neck,  what 
composes  it,  where  the  various  structures  lie  and  their  relation  to  one  another.  In 
order  to  utilize  this  knowledge  we  must  be  able  to  recognize  and  identify  the 
position  of  various  structures  before  the  skin  is  incised,  for  it  is  rarely  that  a  case 
presents  itself  with  a  wound  that  permits  a  view  of  the  deeper  structures;  hence  the 
importance  of  a  thorough  knowledge  of  its  surface  and  the  structures  capable  of 
being  recognized  through  the  skin. 

SURFACE  ANATOMY  OF  THE  NECK. 

For  convenience  of  study  w-e  may  consider  the  structures  in  the  median  line, 
and  those  regions  anterior  and  those  posterior  to  the  sternomastoid  muscle,  between 
it  and  the  trapezius.  The  posterior  portion  of  the  neck  will  be  described  in  the 
section  de\'Oted  to  the  back. 

These  regions  or  triangles  are  simply  arbitrary  divisions,  made  for  conveni- 
ence of  description.      They  are  sometimes  spoken  of  in  reference  to  the  location 


THE    NECK. 


I2g 


of  growths,  operative  incisions,  etc.  They  comprise  the  space  between  the  trapezius 
muscle  posteriorly,  the  median  line  anteriorly,  the  clavicle  below,  and  the  lower  jaw 
above. 

Viewed  from  in  front,  the  median  portion  of  the  neck  may  be  divided  into  three 
regions,  the  submental,  laryngeal,  and  tracheal. 

The  submental  region  extends  from  the  chin  to  the  lower  border  of  the  body 
of  the  hyoid  bone  ;  it  is  limited  laterally  by  the  anterior  belly  of  the  digast?-ic  mus- 
cle on  each  side.  Ranula  and  other  sublingual  tumors  cause  a  bulging  in  this  region 
and  it  is  frequently  occupied  by  an  enlarged  lymphatic  node,  which  at  times  sup- 
purates and  forms  an  abscess.  The  floor  of  the  space  is  formed  by  the  mylokyoid 
muscle  and  there  are  no  dangerous  structures,  so  that  no  hesitancy  need  be  had  in 
incising  abscesses  in  this  locality  nor  in  removing  diseased  lymph-nodes.  In  carci- 
noma involving  the  lower  lip  near  the  median  line  these  nodes  may  be  affected  and 


.interior  belly  of  digastri 
Submaxillary  gland 

Hyoid  bone 
-Thyrohyoid  membrane 

Thyroid  cartilage 
Cricothyroid  membrane 
Cricoid  cartilage 
Stemomastoid  muscle 

Thyroid  gland 


Fig.  i6i. — Anterior  surface  of  the  neck. 

their  involvement  in  such  cases  should  always  be  looked  for.  The  subma.xiiiary 
lymphatic  nodes  farther  outward  may  also  be  implicated.  The  tip  of  the  epiglottis 
projects  above  the  hyoid  bone  in  this  region. 

The  laryngeal  region  extends  from  the  under  surface  of  the  hyoid  bone  to  the 
lower  edge  of  the  cricoid  cartilage.  Laterally  it  is  limited  to  the  space  occupied  by 
the  larynx.  The  cricoid  cartilage  is  included  in  this  region  as  a  part  of  the  larynx. 
The  vocal  cords  are  just  beneath  the  most  prominent  part  of  the  thyroid  cartilage. 

The  tracheal  region  extends  from  the  lower  edge  of  the  cricoid  cartilage  to 
the  top  of  the  sternum.  Just  above  the  sternum,  between  the  sternal  origins  of  the 
stemomastoid  muscles,  is  the  suprasternal  notch  or,  as  it  is  called  by  the  Germans, 
the  Juguluni.      Laterally  the  region  is  limited  by  the  sides  of  the  trachea. 

There  are  seven  or  eight  rings  of  the  trachea  between  the  cricoid  cartilage  and 

the  top  of  the  sternum.      It  is  covered  partly  by  the  sternohyoid  and  sternothyroid 

muscles.      The  former  in  the  lower  half  of  their  course  pass  outv.ard,  leaving  a  space 

in  which  the  sternothyroid  tnuscles  are  seen.     The  sternohyoid  muscle  arises  from 

9 


13° 


APPLIED    ANATOMY. 


the  upper  and  outer  portion  of  the  manubrium,  the  sternoclavicular  ligament,  and  the 
inner  end  of  the  clavicle.  The  origin  of  the  sternothyroid  is  wider  than  that  of  the 
sternohyoid  and  is  lower  down.  It  arises  from  the  first  piece  of  the  sternum  near  the 
median  line,  below  the  sternohyoid,  and  from  the  cartilage  of  the  first  rib.  The  first 
ring  of  the  trachea  is  not  covered  by  any  important  structure.  The  second,  third, 
and  fourth  rings  are  covered  by  the  isthmus  of  the  thyroid  gland;  from  here  down 
the  inferior  thyroid  veins  may  lie  on  the  trachea  for  at  least  part  of  their  course.  The 
anterior fugular  vein  may  exist  either  as  a  single  vein  in  the  median  line  or  to  one 
side  of  it,  or  one  may  pass  downward  on  each  side  of  the  median  line  with  a  communi- 
cating branch  from  one  to  the  other  crossing  the  median  line  in  the  suprasternal  notch. 
The  cricothyroid  artery,  a  small  branch  of  the  superior  thyroid,  may  cross  the  crico- 
thyroid membrane,  but  it  is  usually  too  small  to  cause  any  troublesome  bleeding. 

Structures  to  be  Felt  in  the  Median  Line. — On  passing  the  finger  down- 
ward from  the  s}  mph\  sis  it  smks  mto  a  hollow,  on  crossing  which  the  hyoid  bone  is 


Submaxillary  trj 


Anterior  belly  of  digastnc 


Sternohyoid — 


Anterior  belly  of  • 
omohyoid 


Superior  carotid  triangle 
Occipital  triangle 

Inferior  carotid  triangle 
Trapezius 

Posterior  belly  of  omohyoid 
Subclavian  triangle 


Fig.  162. — Showing  anterior  and  posterior  cervical  and  subsidiary  triangles. 

felt.  On  pressing  the  finger  into  this  hollow  it  rests  between  the  digastric  muscles 
on  each  side  and  the  mylohyoid  muscles  beneath.  Still  deeper  than  the  mylohyoid 
are  the  geniohyoid  and  geniohyoglossus  muscles  attached  to  the  genial  tubercles  on 
the  inner  side  of  the  mandible.  If  the  lymphatic  nodes  at  this  point  are  enlarged 
they  may  be  felt.    (Fig.  161.) 

The  hyoid  bone  can  usually  be  readily  felt  in  the  median  line.  If  it  is  not  easily 
discovered  in  the  median  line  it  can  be  felt  bv  a  finger  and  thumb  placed  on  each 
side  of  the  neck  above  the  thyroid  cartilage. 

Passing  over  the  hyoid  bone  the  finger  then  sinks  into  the  space  between  it  and 
the  top  of  the  thyroid  cartilage.  This  space  is  bridged  by  the  thyrohyoid  mem- 
brane. Next  comes  the  thyroid  cartilage  or  "Adam's  apple."  It  can  readily  be 
seen  in  adult  males  and  thin  people,  but  in  the  fat  necks  of  women  and  children, 
though  it  can  still  be  felt,  it  often  cannot  be  seen.  The  finger  then  sinks  into  the 
space  between  the  thyroid  cartilage  above  and  the  cricoid  below.  They  are  con- 
nected by  the  cricothyroid  membrane,  over  which  runs  a  small  branch  f  cricothyroid) 
of  the  superior  thyroid  artery. 


THE    NECK. 


131 


The  prominence  of  the  cricoid  cartilage  can  be  seen  in  thin  people  and  if  care- 
fully searched  for  can  be  felt  in  almost  all  cases.  It  is  opposite  the  sixth  cervical 
vertebra,  a  most  important  landmark.  From  the  cricoid  cartilage  down  to  the 
sternum  only  soft  structures  can  be  felt.  The  sternum  projects  forward  and  the 
trachea  inclines  backward  so  that  opposite  the  top  of  the  sternum  the  trachea  is  about 
2  cm.  behind  it.  The  distance  between  the  top  of  the  sternum  and  cricoid  cartilage 
in  an  adult  male  is  about  4.5  cm.  (is^  in.). 

THE  CERVICAL  TRIANGLES. 
On  viewing  the  neck  from  the  side  the  prominent  sternocleidomastoid  muscle 
with  its  thick  anterior  and  thin  posterior  edge  is  seen  to  divide  it  into  two  spaces, 
an.  anterior  and  a  posterior.      They  are  called  the  anterior  ajid  poste7'ior  cervical 
triangles. 


External  juguli 


Anterior  belly  of 
digastric 


Fig.  163. — Submaxillary  region,  superficial  structures.     (From  a  dissection.) 


Anterior  Cervical  Triangle. 

The  anterior  cervical  triangle  has  for  its  anterior  side  the  median  line  of  the 
neck.  Its  posterior  side  is  the  anterior  edge  of  the  sternomastoid  muscle.  Its  upper 
side  is  the  lower  edge  of  the  mandible  from  the  symphysis  to  the  angle  and  thence 
across  to  the  mastoid  process.  The  anterior  triangle  is  further  divided  into  the  space 
above  the  digastric  muscle  called  the  submaxillary  triangle, — from  its  containing  the 
gland  of  that  name, — the  superior  carotid  triangle  above  the  anterior  belly  of  the 
omohyoid  muscle,  and  the  inferior  carotid  triangle  below  the  omohyoid  muscle. 

The  submaxilliary  triangle  is  so  called  from  its  containing  the  subma.xillary 
gland.      It  is  also  sometimes  called  the  lingual  triangle,  from  the  lingual  artery.      It 


132 


APPLIED    ANATOMY. 


has  as  its  upper  side  the  lower  edge  of  the  mandible  from  near  its  symphysis  around 
the  lower  edge  of  the  body  to  the  ramus  and  thence  in  a  straight  line  across  to  the 
mastoid  process.  Its  anterior  side  is  the  anterior  belly  and  its  posterior  side  is  the 
posterior  belly  of  the  digastric  muscle.  The  submaxillary  gland  can  usually  be  felt 
beneath  the  jaw.  Beneath  it  runs  the  facial  artery  to  pass  over  the  body  of  the 
mandible  in  front  of  the  anterior  edge  of  the  masseter  muscle.  The  gland  lies  on  the 
hyoglossus  and  mylohyoid  muscles,  which  form  the  floor  of  this  triangle.  It  is 
encased  in  a  sort  of  pocket  formed  by  a  splitting  of  the  deep  cervical  fascia.  The 
posterior  portion  of  this  fascia  runs  from  the  styloid  process  to  the  hyoid  bone  and  is 
called  the  stylohyoid  ligament. 

Lymphatic  nodes  lie  on  the  subma.xillary  gland  and  in  carcinomatous  disease 
they  become  enlarged  and  then  can  be  readil)-  palpated.      In  operating  on  these. 


External  jugular  vein. 
Edge  of  stemomastoid 
muscle' 
Internal  jugul; 


Descendens  hypogL 

External  carotid  art 
Superior  thyroid  artery- 


-  Mylohyoid  muscle 

-  Hyoglossus  muscle 
Digastric  muscle 

-  Hypoglossal  nerve 
Tendon  of  digastric 


Fig.  164. — Deeper  structures  of  the  submaxillary  region,  especially  the  vessels. 

lymphatic  nodes  for  tuberculous  disease,  care  should  be  taken  to  distinguish  between 
them  and  the  submaxillary  gland.  The  tendon  of  the  digastric  muscle  does  not 
come  clear  down  to  the  hyoid  bone  but  the  loop  which  binds  the  two  together  is 
sometimes  a  centimetre  or  more  in  length.  The  lingual  artery  enters  the  sub- 
ma.xillary triangle  near  the  apex  of  the  angle  formed  by  the  tendon  of  the  digastric. 
It  crosses  beneath  the  posterior  belly  of  the  digastric  muscle  and,  particularly  if  the 
digastric  muscles  contract,  it  may  lie  close  to  the  tendon.  Frequently  the  search 
for  it  is  made  too  high  in  the  triangle  and  too  far  away  from  the  hyoid_  bone. 
When  the  submaxillary  gland  is  lifted  from  its  bed  the  hypoglossal  nerve  is  seen 
beneath  lying  on  the  hyoglossus  muscle.  The  lingual  artery  lies  beneath  the  hyo- 
glossus muscle  and  the  muscle  is  cut  through  in  order  to  find  it.  The  submaxillary 
region  is  the  seat  of  Ludwig'  s  angina,  a  septic  inflammation  involving  the  cellular 


THE   NECK. 


133 


tissues  beneath  the  tongue  and  jaw  around  the  submaxillary  gland  and  the  upper 
portion  of  the  neck.  It  is  a  dangerous  affection  and  may  cause  death  not  only  by 
sepsis  but  also  by  oedema  of  the  laryn.x. 

Dr.  T.  Turner  Thomas  {Annals  of  Surgery,  February  and  March,  1908J,  has 
pointed  out  that  the  infection  passes  from  the  inside  of  the  mouth  to  the  submaxil- 
lary region  outside  by  following  the  connective  tissue  around  the  submaxillary  gland 
as  it  winds  around  the  posterior  edge  of  the  mylohyoid  muscle  through  the  opening 
existing  between  this  muscle  in  front  and  the  anterior  portion  of  the  middle  constrictor 
of  the  pharynx  behind. 

The  SUPERIOR  CAROTID  TRIANGLE  is  limited  posteriorly  by  the  sternomastoid 
muscle,  superiorly  by  the  posterior  belly  of  the  digastric,  and  inferiorly  by  the  anterior 
belly  of  the  omohyoid.  The  location  of  the  omohyoid  muscle  can  be  determined 
by  that  of  the  cricoid  cartilage,  as  the  muscle  crosses  the  common  carotid  artery 
about  opposite  that  point.  The  sternomastoid  muscle  can  be  both  seen  and  felt. 
It  is  attached  above  from  the  apex  of  the  mastoid   process  to  the  middle  of  the 


Mylohyoid 

Hypoglossal  nerve 

Digastric 

naxillaiy  gland  (su- 

l1  portion  removed) 

Hyoglossus 


Superior  constr 
Parotid 


Fig.  T65, — Submaxillary  region.  -The  anterior  portion  of  the  submaxillary  gland  is  seen  winding  around 
and  beneatli  the  posterior  edge  of  the  mylohyoid  muscle.  The  posterior  portion  of  the  gland  has  been  cut 
away.    The  posterior  belly  of  the  digastric  and  the  stylohyoid  muscles  have  also  been  removed. 


superior  curved  line  on  the  occipital  bone.  It  is  attached  below  by  a  sternal  head 
to  the  upper  anterior  part  of  the  first  piece  of  the  sternum,  and  by  a  clavicular  head 
to  the  inner  third  of  the  clavicle  on  its  superior  and  interior  border.  Its  action  will 
be  mentioned  in  discussing  wry-neck: 

Arteries. — The  carotid  arteries  and  their  branches  are  found  in  this  triangle. 
The  line  of  the  carotid  arteries  is  from  a  mid-point  between  the  mastoid  process  and 
the  angle  of  the  jaw  to  the  sternoclavicular  articulation.  The  line  of  the  sterno- 
mastoid muscle  is  from  the  mastoid  process  to  near  the  middle  of  the  upper  edge 
of  the  sternum.  Thus  the  carotids  are  internal  to  the  anterior  edge  of  this  muscle  above, 
behind  the  angle  of  the  jaw,  and  e.xternal  to  it  below.  The  common  carotid  at  its 
upper  portion — it  ends  opposite  the  upper  border  of  the  thyroid  cartilage — is  just 
about  at  or  close  to  the  edge  of  the  sternomastoid  muscle.  From  the  thyroid  car- 
tilage up  are  the  internal  and  external  carotids.  The  internal  lies  behind  and  to 
the  outer  side  of  the  external.  The  internal  gives  off  no  branches  until  it  reaches 
the  skull,  while  the  e.xternal  is  practically  all  branches.  Sometimes  the  external  and 
the  internal  carotids  are  covered  by  the  anterior  margin  of  the  sternomastoid  muscle. 
The  branches  of  the  external  carotid  are  the  snpci-ior  thvroid,  ascending  pharyngeal, 
Ungual,  facial,  occipital,  posterior  auricular,  internal  maxillary,  and  temporal.     The 


134 


APPLIED    ANATOMY. 


superior  thyroid  or  the  ascending  pharj-ngeal  may  either  one  be  the  first  given  off 
by  the  external  carotid,  or  may  come  off  from  the  common  carotid  itself  just  before  its 
bifurcation. 

The  superior  thyroid  artery  is  given  oft  in  the  inter\al  between  the  hyoid 
bone  and  upper  border  of  the  thyroid  cartilage.  It  gives  a  small  infrahyoid  branch 
to  the  thyrohyoid  membrane,  also  a  superior  laryngeal  branch  to  the  inside  of  the 
laryn.x.  This  branch  pierces  the  thyrohyoid  membrane  in  companv  with  the  superior 
laryngeal  ner\-e  to  reach  the  interior  of  the  larynx.  The  stcrnomastoid  branch,  to 
the  muscle  of  that  name,  comes  off  at  this  point  and  crosses  the  common  carotid  arterj'. 
It  is  of  some  importance  on  this  account  because  in  ligating  the  common  carotid 
artery  abo\'e  the  omohyoid  muscle  it  is  likely  to  be  cut  and  cause  bleeding.  Another 
branch  of  the  superior  thyroid  artery  is  the  cricothyroid.  It  is  small,  rests  on  th&_ 
cricothyroid  membrane,  and  is  the  first  artery  liable  to  be  cut  in  an  incision  down  the 


^ 


Submaxillary  duct" 
Submaxillary  gl, 
Hypoglossal  nerve' 


Fig.  i66. — Submaxilla 


Lingual  ner\-e 
Superior  constrictor 
Styloglossus 
Parotid  gland 
Hyoglossus 
Middle  constrictor 
Stylohyoid  tendon 
tendon 

yrohyoid 

constrictor 


gion — mylohyoid  muscle  cut  away  showing  the  subliiigual  gland  and  anterior  portion 
of  submaxillary  gland. 


median  line.  Bleeding  from  it  is  not  apt  to  be  serious.  The  remainder  of  the 
superior  thyroid  artery  supplies  the  thyroid  gland. 

The  ascending  pharyngeal  is  a  long  slender  branch  that  comes  from  the 
under  side  of  the  main  trunk.  It  lies  on  the  superior  and  middle  constrictors  of  the 
pharyn.x  and  goes  clear  to  the  skull,  giving  off  some  meningeal  branches.  In  ligat- 
ing the  external  carotid  care  should  be  taken  not  to  include  this  \'essel  in  the  ligature. 
It  also  gi\'es  branches  to  the  soft  palate,  tonsil,  recti  capitis  antici  muscles,  and 
tympanum. 

The  lingual  is  given  of!  just  below  the  greater  horn  of  the  hyoid  bone,  and 
passes  forward  beneath  the  hvoglossus  muscle  to  supply  the  tongue  and  sublingual 
tissues.    The  hypoglossal  nen'e  lies  above  the  artery  and  on  the  hyoglossus  muscle. 

The  facial  comes  off  just  above  the  lingual  artery  or  often  in  a  common  trunk 
with  it.  It  passes  upward  and  forward  in  a  groo\-e  in  the  under  surface  of  the  sub- 
maxillary gland  and  passes  over  the  edge  of  the  jaw  at  the  anterior  border  of  the 
masseter  muscle.      The  facial  vein  at  this  point  is  posterior  to  it. 

The  occipital  artery  comes  off  almost  opposite  the  facial.  It  passes  upward 
and  backward  between  the  mastoid  process  and  the  transverse  process  of  the  atlas, 


THE    NECK. 


135 


then  along  in  the  occipital  groove  beneath  the  origin  of  the  sternomastoid  muscle, 
the  splenius,  trachelomastoid,  and  digastric  to  make  its  appearance  a  little  to  the 
inner  side  of  the  middle  of  a  line  joining  the  mastoid  process  with  the  external  occip- 
ital protuberance. 

The  posterior  auricular  is  given  off  just  above  the  posterior  belly  of  the 
digastric  muscle  and  runs  backward  and  upward  on  it,  then  through  the  parotid 
gland  and  up  between  the  external  auditory  meatus  and  the  mastoid  process.  In 
ligating  the  external  carotid  artery  with  a  view  of  preventing  bleeding  in  removing 
the  Gasserian  ganglion,  it  is  endeavored  to  place  the  ligature  just  above  the  digastric 
muscle  and  posterior  auricular  artery  in  order  to  preserve  the  blood  supply  of  the 


Temporal  artery 


External  carotid  artery 

Posterior  auricular 

arter>' 

Occipital  artery 

Hypoglossal  nerve 

Internal  jugular  vein 

Submaxillary  gland 

Facial  artery 

Internal  carotid  artery 

Lingual  artery 
Superior  laryngeal 

Descendens  hypo- 
Superior  thyroid  artery 
Sternohyoid  branch 


Fig.  167. — Carotid  arteries  and  branches. 

tissues  above  and  behind  the  ear.  The  internal  maxillary  and  the  temporal  arteries 
have  already  been  considered. 

Veins. — The  veins  found  in  and  near  the  superior  carotid  triangle  are  the  anterior 
and  internal  jugulars  and  their  branches.  A  small  portion  of  the  commencement  of  the 
external  jugular  may  also  be  in  its  extreme  upper  angle. 

The  anterior  jugular  vein  begins  just  above  the  hyoid  bone  from  veins  in  the 
submaxillary  and  submental  regions.  It  lies  on  the  deep  fascia  and  passes  down  the 
neck  about  r  cm.  from  the  median  line,  then  just  above  the  sternum  it  turns  down  and 
out  under  the  sternomastoid  muscle  to  empty  into  the  external  jugular  or  subclavian. 
At  the  point  of  turning  it  sends  off  a  branch  across  the  median  line  to  the  vein  on  the 
opposite  side.  Thus  the  blood-current  can  pass  directly  across  the  neck  from  one 
external  jugular  vein  to  the  other.  Sometimes  there  is  another  communication 
between  the  two  anterior  jugulars  through  a  small  branch  crossing  just  above  or 


1.^6 


APPLIED    ANATOMY. 


below  the  hyoid  bone.  Instead  of  two  anterior  jugular  veins  there  may  be  one;  in 
this  case  it  is  likely  to  go  down  the  median  line  o'f  the  neck  and  so  be  wounded  in 
tracheotomy.  It  receives  branches  from  the  inferior  thyroid  veins  and  hence  may 
bleed  freely.      It  has  no  valves. 

The  internal  jugular  vein  lies  to  the  outer  side  of  and  bulges  somewhat  an- 
terior to  the  carotid  arteries.  It  is  formed  by  the  junction  of  the  inferior  petrosal 
and  lateral  sinuses  at  the  jugular  foramen,  and  passes  downward  posterior  to  the 
internal  carotid  artery  and  soon  reaches  its  outer  side.  It  receives  the  facial,  lingual, 
pharyngeal,  superior  and  middle  thyroid,  and  sometimes  the  occipital  veins.  A  large 
communicating  branch  from  the  external  jugular  unites  either  with  the  facial  or  with 
the  internal  jugular,  so  that  a  wound  of  the  external  jugular  may  draw  blood  directly 
from  the  internal  jugular. 

These  tributary  veins  are  superficial  to  the  arteries  and  in  ligating  the  external 
carotid  artery  they  will  have  to  be  displaced.      The  internal  jugular  vein  is  sometimes 


Digastric  muscle 
-Mylohyoid  muscle 
Facial  artery 
Facial  vein 

Submaxillary  gland 
Hyoid  bone 
■Lingual  artery 

-Internal  jugular  vein 
Superior  thyroid  artery 
Omohyoid  muscle 
Sternohyoid  muscle 
Anterior  jugular  vein 

-Cricoid  cartilage 

Sternothyroid  muscle 

Stemomastoid 


Fig.  i68. — Dissection  of  the  deep  structures  of  the  front  of  the  neck. 

excised  in  operations  for  enlarged  lymph-nodes  or  for  infective  thrombus.  It  is  not 
so  large  above  the  facial  vein  as  below  that  point.  It  becomes  so  involved  in  enlarge- 
ments of  both  tuberculous  and  carcinomatous  lymph-nodes  that  it  may  be  neces- 
sary to  excise  it  along  with  the  tumor.  Its  removal  does  not  give  rise  to  any  serious 
symptoms. 

It  becomes  thrombosed  by  the  extension  of  a  thrombus  from  the  transverse 
(lateral)  sinus,  which  in  turn  becomes  aflected  by  the  extension  of  suppurative 
middle-ear  disease  through  the  medium  of  caries  of  the  bones.  When  the  internal 
jugular  is  thrombosed  it  is  evidenced  by  swelling,  redness,  and  tenderness  along- 
the  anterior  border  of  the  stemomastoid  muscle  "just  behind  the  angle  of  the  jaw. 
Bleeding  from  the  veins  in  this  region  is  particularly  dangerous  because  the  internal 
jugular  itself  is  so  large  and  having  no  valves,  will  bleed  both  from  the  side  towards 
the  heart  and  that  towards  the  head. 

The  veins  also,  which  are  tributary  to  it  in  this  region,  are  so  large  and  are 
■wounded  so  close  to  the  main  trunk  that  the  blood  from  the  internal  jugular  itself 


THE    NECK.  137 

regurgitates.  The  walls  of  the  veins  are  thin  and,  if  the  fascias  happen  to  be  rela.xed, 
fall  readily  together  and  thus  are  difficult  to  see,  and  are  so  adherent  to  the  fascias  as 
not  to  be  readily  seized.  The  surgery  of  this  region  requires  extreme  care  and  the 
avoidance  of  haste. 

Nerves. — Lying  between  the  internal  jugular  vein  and  the  internal  and  common 
carotid  arteries  is  the  pneiunogastric  or  tenth  nerve.  It  here  gives  of?  the  superior 
laryngeal  nerve,  the  internal  branch  of  which  enters  the  larynx  through  the  thyro- 
hyoid membrane  to  endow  the  interior  of  the  larynx  with  sensation;  the  external 
branch  goes  to  supply  the  cricothyroid  muscle.  The  pneumogastric  nerve  is  fre- 
quently seen  in  operations  in  this  region.      Its  division  has  not  been  fatal. 

The  hypoglossal  nerve  winds  around  the  occipital  artery  and  goes  forward  on  the 
hyoglossus  muscle,  which  separates  it  from  the  lingual  artery.  The  descendens  hypo- 
glossi  filament  leaves  the  parent  nerve  as  it  winds  around  the  occipital  artery.  It  lies 
on  the  carotid  artery  in  the  form  of  a  loop  formed  by  the  addition  of  branches  froni 
the  second  and  third  cervical  nerves.  As  it  descends  on  the  sheath  of  the  vessels  it 
gives  a  branch  to  the  anterior  belly  of  the  omohyoid  muscle.  The  loop  sends 
branches  to  the  sternohyoid,  sternothyroid,  and  posterior  belly  of  the  omohyoid,  and 
if  the  nerve  is  divided  paralysis  of  these  muscles  will  occur.  The  nerve  is  to  be 
pushed  aside  when  ligating  the  artery  and  not  included  in  the  ligature.  The 
superficial  branches  from  the  cervical  plexus  which  come  from  the  middle  of  the 
posterior  edge  of  the  sternomastoid  muscle  and  ramify  towards  the  median  line, 
are  nerves  of  sensation,  and  their  division  in  operative  work  causes  no  serious  symp- 
toms, hence  they  are  disregarded.  The  inframaxillary  branches  of  the  se\'enth  or 
facial  nerve  supply  the  platysma. 

Lymphatics. — The  lymphatics  are  composed  of  four  sets,  a  superficial  set  along 
the  anterior  border  of  the  sternomastoid  muscle,  a  deep  set  accompanying  the  great 
vessels,  a  submaxillary  set  around  and  on  the  submaxillary  gland,  and  a  set,  two  or 
more  in  number,  beneath  the  chin. 

The  submaxillary  gland  itself  not  infrequently  enlarges  and  is  difficult  to  dis- 
tinguish from  an  enlarged  lymphatic  node.  All  these  glands  are  at  times  subjected 
to  operative  procedures.  Fig.  163  shows  the  submental,  submaxillary,  and  super- 
ficial set  of  lymphatics  enlarged,  as  well  as  the  submaxillary  gland  itself.  It  is  taken 
from  a  tuberculous  subject. 

The  nodes  below  and  behind  the  jaw  become  enlarged  from  diseases  affecting 
the  tongue,  mouth,  and  throat  as  well  as  from  affections  of  the  face  and  scalp. 

The  INFERIOR  CAROTID  TRIANGLE  is  limited  posteriorly  by  the  lower  portion 
of  the  sternomastoid  muscle,  anteriorly  by  the  median  line  of  the  neck,  and  superiorly 
by  the  anterior  belly  of  the  omohyoid  muscle.  In  this  triangle,  or  reached  through  it, 
are  the  lower  portions  of  the  common  carotid  artery  and  internal  jugular  \'ein,  with 
the  pneumogastric  nerve  between.  Anteriorly  are  the  larynx,  trachea,  thyroid  gland, 
and  sternohyoid  and  sternothyroid  muscles.  The  carotid  artery,  jugular  vein,  and 
pneumogastric  nerve  lie  partly  in  the  triangle  but  rather  under  the  edge  of  the 
sternomastoid  muscle.  Operations  on  the  air-passages,  laryngotomy  and  tracheot- 
omy; on  the  thyroid  gland,  thyroidectomy;  and  ligation  of  the  common  carotid 
artery  and  removal  of  lymph-nodes  are  all  done  in  this  triangle.  The  superficial 
and  deep  lymphatics  accompany  the  vessels;  there  are  also  some  in  Burns' s  space 
above  the  sternum.  In  children,  instead  of  the  innominate  artery  ceasing  at  the 
sternoclavicular  articulation,  it  sometimes  rises  above  it  and  may  be  wounded  in 
operation  on  the  trachea.  The  thyroidea  ima  artery,  if  present,  will  lie  on  the 
trachea,  coming  up  from  the  innominate  or  directly  from  the  aorta. 

Posterior  Cervical  Triangle. 
The  posterior  cervical  triangle  has  as  its  base  the  middle  third  of  the  clavicle; 
its  anterior  side  is  the  posterior  edge  of  the  sternomastoid  muscle;  its  posterior  side 
is  the  anterior  edge  of  the  trapezius;  its  ape.x  is  at  the  point  of  junction  of  these  two 
muscles  at  the  superior  curved  line  of  the  occiput.  It  is  customary  to  divide  it  into 
two  triangles  by  the  posterior  belly  of  the  omohyoid  muscle.  The  upper  triangle  is 
large  and  is  called  the  occipital  triangle.  The  lower  triangle  is  small  and  is  called 
the  subclavian  triangle.  This  division  by  the  posterior  belly  of  the  omohyoid 
muscle  is  not  always  satisfactory.      The  muscle  runs  upward  and  inward  in  a  line 


138  APPLIED    ANATOMY. 

from  about  the  junction  of  the  outer  and  middle  thirds  of  the  clavicle  to  a  variable 
distance,  up  to  2.5  cm.  (i  in.),  above  the  clavicle  at  the  anterior  edge  of  the  sterno- 
mastoid  muscle.  The  omoyhoid  muscle  has  its  lower  attachment  at  the  posterior 
edge  of  the  suprascapular  notch,  which  is  below  the  level  of  the  clavicle,  and  its 
posterior  belly  is  sometimes  concealed  behind  the  clavicle  and  does  not  rise  above  it 
except  at  its  inner  extremity  beneath  the  sternomastoid  muscle.  It  is  rare  that  any 
distinct  triangle  is  formed,  hence  as  far  as  the  surface  markings  are  concerned 
there  is  often  no  subclavian  triangle.  Therefore  the  posterior  cervical  triangle  will 
be  considered  as  a  whole  and  not  divided. 

It  is  covered  by  the  skin,  beneath  which  is  the  subcutaneous  tissue,  which  at  its 
lower  portion  contains  the  fibres  of  the  platysma  muscle.  Its  floor  is  composed 
from  above  downward  of  the  splenitis,  levator  scaptdiz,  scalenus  posticus,  scalenus 
medius,  and  scalenus  anticus  muscles.  The  deep  fascia  of  the  neck  spans  the 
space  and  splits  anteriorly  to  enclose  the  sternomastoid  muscle  and  posteriorly  to 


Sternomastoid  muscle 
Anterior  scalene  muscle 
Phrenic  nerve 
Interna]  jugul; 
Omohyoid 


ipitalis  major  nerve 
Occipital  artery 
Occipitalis  minor  nerve 

Splenius  muscle 

:ularis  magnus  nervf 
Superficial  cervical  nerve 
Levator  scapula  muscle 
Spmal  accessory  nerve 
Trapezius' 
Middle  bcalene  muscle 


Pobtenor  scalent 
Fxtemal  jugula 


uscle 


-  Omohyoid  muscle 


enclose  the  trapezius.  The  space  contains  important  arteries,  veins,  nerves,  and 
lymphatics. 

External  Jugular  Vein. — Lying  on  the  deep  fascia  and  beneath  the  super- 
ficial fascia  and  platysma  is  the  external  jugular  vein.  This  begins  below  the  ear 
and  posterior  to  the  ramus  of  the  jaw,  being  formed  by  the  union  of  the  temporo- 
maxillary  and  posterior  auricular  veins.  It  passes  downward  and  slightly  backward 
on  the  surface  of  the  sternomastoid  muscle  to  its  posterior  border,  which  it  reaches  at 
about  the  middle  and  follows  down  until  about  a  centimetre  above  the  clavicle;  here 
it  pierces  the  deep  fascia  and  dips  behind  the  clavicular  origin  of  the  sternomastoid 
muscle  to  empty  into  the  subclavian.  It  has  one  pair  of  vah'es  about  4  cm.  above 
the  clavicle,  and  another  pair  at  its  point  of  entrance  into  the  subclavian.  They  do 
not  entirely  prevent  a  regurgitation  of  the  blood. 

The  external  jugular  vein  receives  the  posterior  external  jugular  vein,  and  the 
suprascapular  and  transverse  cervical  veins.  The  occipital  may  also  enter  mto  it. 
The  veins  of  the  neck  are  exceedingly  irregular  in  their  formation  and  may  vary 
considerably.  The  external  jugular  is  readily  seen  through  the  skin,  _  it  may  be 
made  more  prominent  by  compressing  it  just  above  clavicle.      In  operations  in  this 


THE   NECK.  139 

region  of  the  neck  in  some  cases  it  is  necessary  to  divide  this  vein;  in  others  one 
may  be  able  to  avoid  it,  at  all  events  it  should  be  recognized  before  the  incision  is 
made.  Behind  the  angle  of  the  jaw  there  is  usually  a  branch  communicating  with 
the  facial,  lingual,  or  internal  jugular  vein,  and  just  above  its  lower  extremity  it  is 
enlarged,  forming  the  part  called  the  sinus.  For  these  reasons,  if  the  vein  is  cut  low 
down  near  the  clavicle  or  high  up  near  the  angle  of  the  jaw  bleeding  is  liable  to  be 
free.  The  valves  are  not  competent  to  prevent  the  reflux  of  blood  and  it  therefore 
drains  the  large  internal  jugular  above  and  the  subclavian  below.  The  attachment 
of  the  vein  to  the  deep  fascia,  as  it  pierces  it  above  the  cla\-icle,  tends  to  keep  its 
lumen  open  when  the  vein  is  divided  and  favors  the  entrance  of  air  into  the  circula- 
tion. The  size  of  the  veins  in  the  posterior  triangle  varies  according  to  those  in  the 
anterior.  If  the  anterior  and  external  jugulars  are  large  the  posterior  and  internal 
jugulars  are  apt  to  be  small. 

Arteries. — The  arteries  in  the  posterior  cervical  triangle  are  the  subclaviaii,  the 
transverse  cervical,  and  sometimes  the  suprascapular  when  it  runs  above  the  clavicle 
instead  of  behind  it.  The  line  of  the  subclavian  is  from  the  sternoclavicular  joint  to 
the  middle  of  the  clavicle.  It  rises  about  1.25  cm.  {Y>  in.)  above  the  clavicle.  The 
clavicular  origin  of  the  sternomastoid  muscle  covers  the  inner  third  of  the  clavicle  so  that 
the  subclavian  artery  is  only  visible  in  the  posterior  cervical  triangle  from  the  outer 
edge  of  this  muscle  to  the  middle  of  the  clavicle.  Both  the  suprascapular  and 
transverse  cervical  arteries  are  given  ofl  from  the  thyroid  axis,  which  arises  from  the 
third  portion  of  the  subcla\'ian  just  internal  to  the  scalenus  anticus  muscle.  Therefore 
at  their  origin  they  are  both  considerably  above  the  level  of  the  clavicle,  but  as  they 
proceed  outward  they  incline  downward,  and  on  leaving  the  outer  edge  of  the  sterno- 
mastoid muscle  the  suprascapular  is  usually  behind  the  clavicle  while  the  transverse 
cervical  runs  parallel  to  it  and  a  short  distance  ( i  cm. )  above  it,  where  it  can  be 
felt  pulsating. 

The  posterior  belly  of  the  omohyoid  muscle  can  be  represented  by  a  line  drawn 
from  the  anterior  edge  of  the  sternomastoid  muscle  opposite  the  cricoid  cartilage, 
obliquely  down  and  out  to  the  junction  of  the  middle  and  outer  thirds  of  the  clavicle. 
It  is  superficial  to  the  transverse  cervical  artery  and  at  its  inner  end  is  abo\^e  it. 
These  arteries  and  their  accompanying  veins  will  be  encountered  in  operating  in 
these  regions  for  the  removal  of  lymphatic  nodes. 

Nerves. — The  nerves  in  the  posterior  cervical  triangle  are  the  spinal  accessory, 
branches  of  the  cervical  plexus,  and  the  brachial  plexus.  The  position  of  the  spinal 
accessory  is  important  because  it  is  frequently  encountered  in  operations  for  the 
removal  of  enlarged  lymphatic  nodes.  It  enters  the  under  surface  of  the  sternomastoid 
muscle  from  3  to  5  cm.  below  the  tip  of  the  mastoid  process  and  emerges  at  the  pos- 
terior edge  about  its  middle  or  a  little  above.  It  is  about  at  this  point  that  the. 
external  jugular  vein  reaches  the  posterior  border  of  the  sternomastoid,  and  the  cervical 
plexus,  formed  by  the  anterior  divisions  of  the  four  upper  cervical  nerves,  reaches 
the  surface.  From  this  point  also  the  occipitalis  minor  runs  upward  along  the  posterior 
edge  of  the  sternomastoid  and  the  aui-icularis  magnus  runs  upward  over  the  sterno- 
mastoid direct  to  the  e.xternal  ear.  The  superficial  cervical  runs  directly  across  the 
muscle  towards  the  median  line  and  the  descending  branches — the  sternal,  cla^'icular, 
and  acromial — pass  down  beneath  the  deep  cervical  fascia  to  perforate  it  just  above  the 
clavicle  and  become  cutaneous.  Care  should  be  taken  not  to  mistake  them  for  the 
spinal  accessory.  Still  deeper  are  the  cords  of  the  brachial  plexus.  These  cords, 
sometimes  two,  at  others  three  in  number,  are  beneath  the  deep  fascia  and  lie  above 
the  subclavian  artery.  They  can  be  felt  and  in  a  thin  person,  if  the  head  is  turned  to 
the  opposite  side,  the  prominence  which  they  form  under  the  skin  can  e\'en  be  seen. 

Lymphatics. — The  l3miphatics  of  the  posterior  cervical  triangle  are  numerous 
and  being  often  enlarged  are  frequently  operated  on.  They  lie  along  both  the  outer 
side  of  the  internal  jugular  vein  and  under  the  posterior  edge  of  the  sternomastoid 
muscle,  which  they  follow  clear  up  to  the  base  of  the  skull.  They  also  follow  the  edge 
of  the  trapezius  muscle  and  lie  in  the  space  between  it  and  the  sternomastoid;  they 
extend  downward  under  the  clavicle  and  become  continuous  with  the  axillary 
lymphatics.  The  right  and  left  lymphatic  ducts  empty  into  the  venous  svstem  at 
the  junction  of  the  innominate  and  internal  jugular  veins.     That  on  the  left  side  is 


I40  APPLIED    ANATOMY. 

called  the  thoracic  duct ;  it  begins  as  the  receptaculum  chyli  on  the  body  of  the 
second  lumbar  vertebra  and  is  about  45  cm.  (18  in. )  long.  It  drains  all  the  left  side 
of  the  bod)'  and  the  right  as  far  up  as  and  including  the  lower  surface  of  the  liver. 

The  duct  on  the  right  side  is  called  the  right  lymphatic  duct ;  it  is  only  i  or  2 
cm.  in  length  and  drains  the  right  side  of  the  head  and  neck,  the  right  upper  ex- 
tremity, and  the  right  side  of  the  chest  as  far  down  as  and  including  the  upper  surface 
of  the  liver. 

TORTICOLLIS  OR  WRY-NECK. 

In  this  affection  the  head  and  the  neck  are  so  twisted  that  the  face  is  turned 
toward  the  side  opposite  the  contracted  muscle  and  looks  somewhat  up\^'ard.  It  is 
usually  caused  by  some  affection  of  the  sternomastoid  muscle.  It  is  not  always  th^ 
only  muscle  involved,  as  tlie  trapezius  and  others  may  likewise  be  affected.  It  is 
congenital  or  acquired.      In   the  congenital  cases  it  is  caused  by  an  injury  to  the 


sternomastoid  muscle,  occurring  during  childbirth;  a  swelling  or  tumor  may  be 
present  in  the  course  of  the  muscle.  In  the  acquired  form  the  distortion  may  be 
more  or  less  permanent  and  mav  be  due  to  caries  or  other  disease  of  the  spine.  In 
such  cases  it  is  evident  that  treatment  is  to  be  directed  to  the  diseased  spine  rather 
than  to  the  sternomastoid  muscle. 

Inflammation  of  the  lymph-nodes  of  the  neck  may  cause  the  patient  to  hold  the 
head  and  neck  in  a  distorted  position.  The  wry-neck  in  this  case  will  disappear  as 
the  cause  subsides.  Rheumatic  affections  of  the  neck  are  a  common  cause,  and  the 
sternomastoid  muscle  may  then  become  contracted  and  require  division.  In  rare 
instances  a  nervous  affection  causes  a  spasmodic  torticollis.  The  persistent  move- 
ments render  this  a  very  distressing  affection,  and  to  relie^'e  it  not  only  has  the 
sternomastoid  but  also  the  trapezius  been  divided,  and  even  the  spinal  accessory  and 
occipital  nerves  ha\-e  been  excised. 

Division  of  the  sternomastoid  muscle  should  be  done  by  ojien  and  not  b)'  sub- 
cutaneous incision.  The  sternal  origin  of  the  sternomastoid  muscle  is  a  sharp,  dis- 
tinct cord,  but  its  clavicular  origin  is  a  broad,  thin  band  extending  outward  a  third  of 
the  length  of  the  clavicle.  An  incision  2  or  3  cm.  or  more  in  length  is  made  o\-er 
the  tendon  and  the  bands  are  to  be  carefullv  isolated  before  being  di\'ided.  The 
structure  most  important  to  a\'oid  is  the  internal  jugular  vein.  It  lies  close  behind 
the  sternal  origin  of  the  muscle  and  great  care  must  be  taken  to  avoid  it.  In  one 
case   in  which  it  was  accidentally  wounded  it  was  necessary  to  ligate  it.      As  the 


THE    NECK.  Ui 

deep  fascia  of  the  neck  splits  to  enclose  the  sternomastoid  muscle  it  is  opened  by 
the  operation  and  infection  has  caused  in  such  cases  wide-spread  phlegmonous 
inflammation. 

ARTERIES    OF   THE   NECK.— LIGATION. 

Carotid  and  Subclavian  Arteries  and  Branches. — Both  these  arteries  are 
affected  at  times  with  aneurisms,  necessitating  their  ligation.  Ligation  of  the  main 
trunks  or  their  branches  is  also  required  in  various  operations  on  the  head,  as  in  re- 
moval of  the  Gasserian  ganglion  or  maxilla,  or  excision  of  the  tongue,  thyroid  gland, 
etc.  The  communication  between  the  arteries  on  the  two  sides  of  the  body  is  quite 
free,  as  also  is  that  between  the  arteries  above  and  those  lower  down.  For  this 
reason  bleeding  from  the  distal  end  of  a  cut  arter)-  will  be  almost  as  free  as  from  its 
proximal  end.  The  various  branches  of  the  external  carotid  anastomose  across  the 
median  line  of  the  body.  The  vertebrals  communicate  above  through  the  basilar. 
The  internal  carotids  communicate  through  the  anterior  cerebral  and  anterior  com- 
municating and  with  the  basilar  through  the  posterior  communicating  and  posterior 
cerebral.  Between  the  parts  above  and  those  below  we  have  the  superior  thyroid 
anastomosing  with  the  inferior  thyroid  branch  of  the  thyroid  axis  from  the  subclavian 
artery.  The  princeps  cervicis,  a  branch  of  the  occipital,  anastomoses  with  the  as- 
cending cervical  branch  of  the  inferior  thyroid,  the  transverse  cer\'ical  of  the  thyroid 
axis,  and  the  profunda  cervicis  from  the  superior  intercostal.  These  free  communi- 
cations enable  the  surgeon  to  ligate  to  any  extent  without  incurring  the  risk  of  gan- 
grene. The  line  of  the  carotid  arteries  is  from  a  point  midway  between  the  mastoid 
process  and  the  angle  of  the  jaw  to  the  sternocla\'icular  articulation.  At  the  upper 
border  of  the  thyroid  cartilage  the  common  carotid  divides  into  the  internal  and  ex- 
ternal carotids;  this  is  opposite  the  fifth  cervical  vertebra. 

Common  Carotid  Artery. — This  lies  on  the  longus  colli  muscle  and  a  small 
portion  of  the  rectus  capitis  anticus,  which  separate  the  artery  from  the  transverse 
processes  of  the  vertebrje.  The  artery  can  be  compressed  against  the  vertebrae  and 
its  pulsations  stopped  by  pressing  backward  and  slightly  inward.  It  is  superficial  in 
the  upper  portion  of  its  course  but  becomes  deeper  as  it  approaches  the  chest.  The 
anterior  tubercle  of  the  transverse  process  of  the  sixth  cervical  vertebra  is  called 
Chassaignac' s  tubercle.  It  is  about  opposite  the  cricoid  cartilage.  It  is  one  of  the 
guides  to  the  artery.  The  omohyoid  muscle  crosses  the  artery  opposite  the  cricoid 
cartilage  and  just  above  it  is  the  site  of  election  for  ligation. 

Ligation  of  the  Common  Carotid  Artery. — In  making  the  incision,  which  should 
be  5  or  6  cm.  long,  it  should  be  laid  along  the  anterior  edge  of  the  sternomastoid 
muscle  with  its  middle  opposite  to  or  a  little  abo\'e  the  level  of  the  cricoid  cartilage. 
This  incision  may  be  a  little  anterior  to  the  direct  line  of  the  artery  as  given  from 
midway  between  the  angle  of  the  jaw  and  mastoid  process  to  the  sternoclavicular 
articulation.  This  is  because  the  muscle  bulges  forward  and  overlaps  and  hides  the 
artery.  The  artery  is  beneath  its  edge.  On  cutting  through  the  superficial  fascia  and 
platysma  the  deep  fascia  is  reached,  some  small  veins  perhaps  being  divided  in 
so  doing.  The  deep  fascia  is  divided  along  the  edge  of  the  sternomastoid  muscle, 
which  is  then  pulled  outward.  Beneath  it  and  running  obliquely  across  the  lower 
portion  of  the  wound  is  the  omohyoid  muscle.  It  is  recognized  by  the  direction  of 
its  fibres,  they  being  more  or  less  transverse  or  oblique.  Sometimes  a  small  artery, 
the  sternomastoid  branch  of  the  superior  thyroid,  crosses  the  common  carotid  just 
above  the  omohyoid  muscle.  The  artery  is  also  crossed  by  veins.  The  lingual, 
superior,  and  middle  thyroid  veins  all  pass  over  it  to  enter  the  internal  jugular. 
The  middle  thyroid  vein  may  be  above  or  just  below  the  omohyoid  muscle. 
These  vessels  all  pass  transversely  across  the  artery  and  beneath  the  deep  fascia. 
The  artery  lies  in  a  separate  sheath  to  the  inner  side  of  the  jugular  vein.  In  the 
living  body  it  is  to  be  recognized  by  its  pulsations.  The  vein  being  filled  with  blood 
may  overlap  the  artery.  Veins  are  readily  emptied  of  their  blood  by  pressure  on 
the  parts  during  the  operation ;  hence  if  the  vein  happens  to  be  collapsed  it  may  not 
be  recognized  and  is  liable  to  be  wounded.  Therefore  in  examining  for  the  artery  see 
that  the  pressure  from  the  retractors  or  other  sources  does  not  obstruct  the  flow  of 


142  APPLIED   ANATOMY. 

blood  through  the  jugular  vein.  Running  down  on  the  anterior  surface  of  the 
artery  is  the  descendens  hypoglossi  nerve.  If  seen  it  should  be  pushed  aside.  It 
supplies  the  sternohyoid,  sternothyroid,  and  both  bellies  of  the  omohyoid  muscles. 
The  pneumogastric  nerve  lies  posteriorly,  between  the  artery  and  the  vein.  Care 
will  be  necessary  to  avoid  including  it  in  the  ligature.  The  ligature  is  to  be  carried  from 
the  outer  to  the  inner  side,  the  needle  being  passed  between  the  vein  and  the  artery. 
Ligation  of  the  Conmion  Carotid  Artery  Beloio  the  Omohyoid  Muscle. — The  artery 
below  the  omohyoid  muscle  becomes  deeper  and  less  accessible.  The  sternohyoid 
muscle  overlaps  it  and  is  less  easily  displaced.  The  sternohyoid  and  sternothyroid 
muscles  likewise  tend  to  encroach  on  it  and  have  to  be  drawn  inward.  The  internal 
jugular  vein  and  carotid  artery  diverge  as  they  descend,  so  that  at  the  level  of  the 
sternoclavicular  joint  they  are  separated  2. 5  cm.  In  this  interval  the  first  portion 
of  the  subclavian  artery  shows  itself.  The  anterior  jugular  \&.\\  will  probably  be 
encountered  along  the  edge  of  the  sternomastoid  muscle,  and  near  the  omohyoid 


Stemomastoid  artery 
Common  carotid  artery 
Descendens  hypoglossi  nerve 
Internal  jugular  vein 
Stemomastoid  muscle 
)hyoid  muscle 


Fig.  171. — Ligation  of  the  common  carotid  artery. 


muscle  the  artery  will  be  crossed  by  the  middle  thyroid  vein.  Still  lower  it  may  be 
that  the  inferior  thyroid  will  be  encountered.  Posterior  to  the  carotid  artery  is  the 
inferior  thyroid  artery,  coming  from  the  thyroid  axis  and  going  to  the  thyroid  gland, 
and  winding  around  from  posteriorly  to  the  inner  side  is  the  recurrent  laryngeal 
nerve.      The  ligating  needle  is  to  be  passed  from  without  in\^-ard. 

Collateral  Circulation  After  Ligation  of  the  Common  Carotid  Artery. — When 
the  common  carotid  has  been  tied  the  blood  reaches  the  parts  beyond  from  the 
branches  of  the  carotid  of  the  opposite  side  and  from  the  subclavian  artery  of  the 
same  side.  The  branches  of  the  external  carotid  anastomose  across  the  median  line. 
This  is  particularly  the  case  with  the  superior  thyroid  and  facial.  The  internal 
carotids  communicate  by  means  of  the  circle  of  Willis.  From  the  subclavian  the 
vertebral  artery  communicates  by  means  of  the  basilar  with  the  circle  of  Willis. 
The  thyroid  axis  by  its  inferior  thyroid  branch  communicates  with  the  thyroid 
arteries  of  the  opposite  side.  An  ascending  branch  of  the  inferior  thyroid  as  well  as 
one  from  the  transverse  cervical,  also  from  the  thyroid  axis,  anastomose  with 
branches  of  the  princeps  cervicis,  which  is  a  descending  branch  of  the  occipital. 


THE   NECK. 


143 


Finally  the  superior  intercostal,  which,  like  the  vertebral  and  thyroid  _  axis,  is  a 
branch  of  the  first  portion  of  the  subclavian,  through  its  profunda  cervicis  branch 
anastomoses  with  a  deep  descending  branch  of  the  princeps  cervicis  (Fig.  172). 

The  Internal  Carotid  Artery. — The  internal  carotid  lies  posterior  and  to 
the  outer  side  of  the  external.  It  gives  of!  no  branches  in  the  neck.  Entering  the 
skull  through  the  carotid  canal,  in  the  apex  of  the  petrous  portion  of_  the  temporal 
bone  and  direcdy  below  and  to  the  inner  side  of  the  Gasserian  ganglion,  it  passes 
through  the  inner  side  of  the  cavernous  sinus  and  at  the  anterior  clinoid  processes  it 
bends  up  to  divide  into  the  anterior  and  middle  cerebrals.  Before  its  division  it 
gives  off  the  posterior  communicating  artery,  the  ajiterior  choroid  artery  to  supply 
the  choroid  plexus  in  the  lateral  ventricles,  and  the  ophthalmic  artety.     The  internal 


Temporal 

Posterior  auricular 

Occipital 

Princeps  cervicis 

Superficial  branch 

Deep  branch 

Internal  carotid 


Transverse  cervical 
Suprascapul 


Ascending  pharyngeal 
Facial 


Superior  intercostal 


^        WW  w        I 

.  172. — Collateral  circulation  after  ligation  of  the  common  carotid  artery 


carotid  artery  in  the  neck  is  normally  straight,  but  sometimes,  particularly  in  elderly 
persons,  it  is  tortuous.  This  may  then  be  mistaken  for  aneurism.  It  lies  about  2  cm. 
posterior  and  a  litde  to  the  outer  side  of  the  tonsil.  As  the  pharynx  is  the  side  of 
least  resistance,  when  the  vessel  becomes  tortuous  it  bulges  into  it,  and  on  examina- 
tion through  the  mouth  a  pulsating  swelling  can  be  distincdy  seen  in  the_  pharynx 
just  posterior  to  the  tonsil.  The  finger  introduced  can  feel  the  pulsations,  and 
pressure  on  the  carotid  in  the  neck  below  causes  the  pulsations  to  cease.  Thus  the 
character  of  the  pulsating  swelling  can  be  recognized.  This  artery  is  rarely  ligated, 
but  if  it  is  desired  to  do  so  it  can  readily  be  reached  through  an  incision  6  or  7  pm. 
long  behind  the  angle  of  the  jaw.  Aneurism  or  wounds  may  necessitate  its  ligation. 
At  its  commencement  it  is  comparatively  superficial,  but  as  it  ascends  it  gets  quite 
deep,  passing  beneath  the  digastric  and  stylohyoid  muscles.  It  should  therefore  be 
ligated  below  the  angle  of  the  jaw  and  not  over  3  cm.  from  its  origin  at  the  upper 


144  APPLIED    ANATOMY. 

border  of  the  thyroid  cartilage.  It  will  be  necessary  to  push  the  sternomastoid 
muscle  posteriorly,  as  its  anterior  margin  overlies  the  vessel.  The  internal  jugular 
vein  is  to  its  outer  side  and  between  the  two  and  posterior  is  the  pneumogastric 
nerve.  The  svinpathetic  neife  lies  behind  it  but  is  separated  by  a  layer  of  fascia  and 
is  not  liable  to  be  caught  up  in  passing  the  aneurism  needle.  The  lingual,  facial, 
and  laryngeal  veins  may  be  encountered  and  are  apt  to  cause  trouble.  They  will 
ha\'e  to  be  held  aside  or  ligated  and  di\'ided.  The  ascending  pharyngeal  artery  may 
lie  close  to  the  internal  carotid  and  care  should  be  taken  not  to  include  it  in  the 
ligature.      The  needle  is  to  be  passed  from  without  inward. 

The  External  Carotid  Artery. — Of  recent  years  the  external  carotid  artery 
has  been  ligated  far  more  often  than  formerly,  as  it  was  customary  to  ligate  the 
common  carotid  instead.  The  external  carotid  runs  from  the  upper  border  of  the 
thyroid  cartilage  to  the  neck  of  the  mandible.  It  supplies  the  outside  of  the  head, 
face,  and  neck.  These  parts  are  the  seat  of  various  operations  for  tumors,  especially 
carcinoma  of  the  mouth  and  tongue,  diseased  lymph-nodes,  and  other  affections,  and 


Facial  artery 
Lingual  artery, 

Greater  comu  of 
hyoid  bone 
Superior  laryn- 
geal nerve 
Ext.  carotid  artery 
Superior  thyroid 
artery 


Stylohyoid  muscle 
Digastric  muscle 
Occipital  artery 
Hypoglossal  nerve 
Descendens  hypoglossi 


Internal  carotid  artery 
Internal  jugular  vein 


Supe 

)mastoid  artery 
Common  carotid  artery^ 

Fig.  173. — Ligation  of  external  carotid  artery  and  its  branches. 

the  external  carotid  and  its  branches  are  not  infrequently  ligated  in  order  to  cut  off 
their  blood  supply. 

In  extirpation  of  the  Gasserian  ganglion,  hemorrhage  has  been  such  an  annoying 
and  dangerous  factor  that  a  preliminary  ligation  or  compression  ( Crile )  of  the 
external  carotid  is  frequently  resorted  to.  This  artery  may  also  be  ligated  for 
wounds,  resection  of  the  upper  jaw,  hemorrhage  from  the  tonsils,  and  angiomatous 
growths  affecting  the  region  which  it  supplies. 

Unlike  some  other  arteries  the  external  carotid  sometimes  seems  to  have  no 
trunk,  consisting  almost  entirely  of  branches.  Therefore  in  ligating  it  one  should 
not  expect  to  find  a  big  artery  the  size  of  the  internal  carotid,  but  often  one  only  half 
as  large.  The  branches  of  the  external  carotid  artery  are  the  superior  thyroid,  lin- 
gual, and  facial,  which  proceed  anteriorly  toward  the  median  line  :  the  occipital 
and  posterior  auricular,  which  supply  the  posterior  parts  ;  the  ascending  pharyngeal, 
which  comes  oft"  from  its  deep  surface  and  ascends  to  the  base  of  the  skull  ;  and 
the  temporal  and  internal  maxillary  arteries,  which  are  terminal.  It  is  ligated  either 
near  its  commencement  just  abo\'e  the  superior  thyroid  artery  or  behind  the  angle 
of  the  jaw  above  the  digastric  muscle. 

Ligatio7i  of  the  External  Carotid  Artery  above  the  Superior  Thyroid.— -At  its 
commencement  at  the  upper  border  of  the   thyroid   cartilage  the  artery  is  quite 


THE   NECK.  145- 

superficial,  being  covered  by  the  skin,  superficial  fascia,  platysma,  deep  fascia,  and 
overlying  edge  of  the  sternomastoid  muscle.  It  is  to  be  reached  through  an  incision 
5  cm.  in  length  along  the  anterior  edge  of  the  sternomastoid  muscle  in  a  line  from 
the  sternoclavicular  joint  to  midway  between  the  angle  of  the  jaw  and  the  mastoid 
process.  The  middle  of  the  incision  is  to  be  opposite  the  thyrohyoid  membrane. 
The  bifurcation  of  the  common  carotid  artery  is  an  important  landmark. 

The  superior  thyroid  artery  is  given  off  at  the  very  commencement  and  some- 
times even  comes  from  the  common  carotid  just  below.  The  ascending  pharyngeal 
is  the  next  branch,  about  i  cm.  above  the' superior  thyroid.  It  comes  off  from  the 
deep  surface  of  the  artery  ;  almost  opposite  to  it  and  in  front  is  the  lingual.  It  will 
thus  be  seen  that  the  distance  between  the  lingual  and  the  superior  thyroid,  where 
the  ligature  is  to  be  placed,  is  quite  small.  The  superior  thyroid  is  about  opposite 
the  upper  border  of  the  thyroid  cartilage,  while  the  lingual  is  opposite  the  hyoid 
bone.  Beneath  the  artery  is  the  superior  laryngeal  nerve,  but  it  is  not  liable  to  be 
caught  up  by  the  needle  in  passing  the  ligature  because  it  lies  flat  on  the  constrictors 
of  the  pharynx  and  is  apt  to  be  a  little  above  the  site  of  ligation. 

The  veins  are  the  only  structures  liable  to  cause  trouble.  They  are  superficial 
to  the  arteries.  On  account  of  their  irregularity  more  may  be  encountered  than  is 
expected.  The  superior  thyroid  and  lingual  veins  both  cross  the  artery  to  empty 
into  the  internal  jugular.  The  facial  vein  is  also  liable  to  be  met,  as  the  facial  artery 
frequently  springs  from  a  common  trunk  with  the  lingual.  The  communicating 
branch  between  the  facial  and  external  jugular  vein  is  another  one  that  should  be 
anticipated.  These  veins,  when  it  is  possible,  are  to  be  hooked  aside;  otherwise 
they  are  to  be  ligated  and  cut.  Great  care  should  be  taken  not  to  mistake  a  vein 
for  the  artery.  It  might  appear  an  easy  matter  to  readily  recognize  the  artery  and 
distinguish  between  it  and  the  veins,  but  this  is  not  always  the  case  in  the  living 
subject.  The  veins  may  ha\-e  some  pulsation  transmitted  to  them  from  the  adjacent 
arteries  and  the  artery  may  temporarily  have  its  pulsations  stopped  by  pressure  from 
the  retractors.  The  living  artery  touched  by  the  finger  seems  soft  and  does  not  give 
the  hard,  resisting  impression  felt  in  palpating  the  radial  in  feeling  the  pulse.  The 
difference  in  thickness  of  the  coats  is  also  sometimes  not  apparent  at  a  first  glance. 

The  ligature  is  to  be  passed  from  without  inward  so  as  to  guard  against  wounding 
the  internal  carotid. 

Ligation  of  the  Superior  Thyroid  Artery. — The  superior  thyroid  is  the  first 
branch  of  the  e.xternal  carotid  and  is  given  off  close  down  to  the  bifurcation  or  even 
from  the  common  carotid  itself  just  below.  It  lies  quite  superficial  but  of  course 
beneath  the  deep  fascia.  At  first  it  inclines  upward  and  then  makes  a  bend  and  goes 
downward  to  the  thyroid  gland.  It  gi\'es  off  three  comparatively  small  branches, 
the  hyoid  along  the  lower  border  of  the  hyoid  bone,  the  sternomastoid  to  the  muscle 
of  that  name,  and  the  superior  laryngeal  to  the  interior  of  the  larynx.  The  larger 
portion  of  the  artery  goes  downward  to  supply  the  thyroid  gland  and  muscles  over 
it,  therefore  the  artery  is  to  be  looked  for  at  the  upper  edge  of  the  thyroid  cartilage, 
and  not  near  the  hyoid  bone.  The  incision  is  the  same  as  for  ligating  the  e.xternal 
carotid  low  down,  viz. ,  5  cm.  along  the  anterior  edge  of  the  sternomastoid  muscle,  its 
middle  being  opposite  the  upper  edge  of  the  thyroid  cartilage.  Veins  from  the  thyroid 
gland — superior  thyroid — will  probably  cover  it.  After  the  deep  fascia  has  been 
opened,  the  external  carotid  is  to  be  recognized  at  its  origin  from  the  common  carotid 
and  then  the  superior  thyroid  artery  found  and  followed  out  from  that  point.  The 
ligature  is  to  be-  passed  from  above  downward  to  avoid  the  superior  laryngeal  nerve. 
This  nerve  lies  distinctly  above  the  artery  and  is  not  liable  to  be  injured  if  the  thyroid 
artery  is  followed  out  from  its  origin  at  the  external  carotid.  Treves  suggests  ligat- 
ing it  between  the  sternomastoid  and  superior  laryngeal  branches,  but  it  is  more 
readily  reached  closer  to  the  external  carotid  artery. 

Ligation  of  the  Lingual  Artery . — The  lingual  artery  may  be  ligated  for  wounds, 
as  a  preliminary  step  to  excision  of  the  tongue,  and  to  check  the  growth  of  or  bleed- 
ing from  malignant  growths  of  the  tongue,  mouth,  or  lower  jaw. 

The  lingual  artery  springs  from  the  external  carotid  opposite  the  hyoid  bone 
about  I  cm.  above  the  bifurcation  of  the  common  carotid.  It  is  composed  of  three 
parts:   the  first,   from  its  point  of  origin  to  the  posterior  edge  of  the  hyoglossus 


146 


APPLIED    ANATOMY. 


muscle;  the  second,  the  part  beneath  the  hyoglossus  muscle;  and  the  third,  the  part 
beyond  this  muscle  to  the  tip  of  the  tongue. 

The  artery  is  usually  ligated  beneath  the  hyoglossus  muscle  in  the  second  part  of 
its  course,  although  it  is  sometimes  desirable  to  ligate  it  in  the  first  part  of  its  course. 

The  Jirst  part  inclines  upward  and  forward,  above  the  greater  horn  of  the  hyoid 
bone,  to  the  hyoglossus  muscle,  beneath  which  it  passes  in  a  direction  somewhat 
parallel  to  the  upper  edge  of  the  hyoid  bone.  It  lies  on  the  middle  constrictor  of 
the  pharynx  and  superior  larnygeal  nerve  and  is  covered  by  the  skin,  platysma,  and 
fascia.  It  lies  immediately  below  the  stylohyoid  and  digastric  muscles  and  is  crossed 
by  the  hypoglossal  nerve  and  some  veins.  This  portion  frequently  gives  off  a  hyoid 
branch  which  runs  above  the  hyoid  bone.  It  is  often  missing,  in  which  case  the 
parts  are  supplied  by  the  hyoid  branch  of  the  superior  thyroid.  From  either  the  end 
of  the  first  part  or  the  beginning  of  the  second  part,  the  dorsalis  linguae  branch  arises. 

The  second  part  of  the  lingual  lies  on  the  superior  constrictor  and  geniohyoglos- 
sus  muscles  and  is  covered  by  the  hyoglossus.  It  runs  in  a  direction  somewhat 
parallel  to  the  upper  edge  of  the  hyoid  bone  and  from  0.5  to  i  cm.  above  it.      In  this 


<^' 


Mylohyoid  muscle 

Submaxillary  gland  — 

Anterior  belly  of 
digastric  muscle 

Lingual  artery 

Tendon  of 
digastric  muscle 


Fig.  174. — Ligation  of  the 


Hypoglossal  i 
Lingual  ■< 
edge  of  the  hyoglossus  i 
ngual  artery 


Cut  ( 


part  of  its  course  it  is  usually  accompanied  by  one  or  two  veins  and  the  hypoglossal 
nerve  is  superiicial  to  it,  the  hyoglossus  muscle  separating  them.  This  is  the  part 
of  the  artery  chosen  for  ligation.  An  incision  is  made,  convex  downward,  running 
from  below  and  to  one  side  of  the  symphysis  nearly  down  to  the  hyoid  bone  and 
then  sloping  upward  and  back,  stopping  short  of  the  line  of  the  facial  artery,  which 
can  be  determined  by  the  groove  on  the  mandible  just  in  front  of  the  masseter  muscle. 
The  skin,  superficial  fascia,  and  platysma  having  been  raised,  the  submaxillary  gland 
is  seen  covered  with  a  comparatively  thin  deep  fascia.  Some  veins  coming  from  the 
submental  region  may  then  be  encountered.  They  may  be  ligated  and  divided. 
The  submaxillary  gland  is  next  to  be  lifted  from  its  bed  and  turned  upward  against 
the  mandible,  carrying  with  it  the  facial  artery,  which  is  adherent  to  its  under  sur- 
face. The  tendon  of  the  digastric  will  now  be  seen  with  the  anterior  and  posterior 
bellies  of  the  muscle  forming  an  angle  with  its  point  toward  the  hyoid  bone.  These 
with  the  hypoglossal  nerve  form  what  has  been  called  the  triangle  of  Lesser.  It  is 
in  this  space  that  the  artery  is  ligated.  The  floor  of  the  space  posteriorly  is  formed 
by  the  hyoglossus  muscle,  while  anteriorly  is  seen  the  edge  of  the  mylohyoid  muscle. 
Through  the  thin  fascia  overlying  the  hyoglossus  muscle  can  be  seen  the  hypoglossal 


THE    NECK.  147 

nerve,  and  below  it,  sometimes  a  vein.      The  artery  lies  under  the  muscle,  while  the 
veins  may  be  either  on  or  under  the  muscle  or  both. 

The  apex  of  the  angle  formed  by  the  tendon  of  the  digastric  muscle  is  held 
down  to  the  hyoid  bone  by  a  slip  of  fascia  which  is  an  expansion  of  the  central 
tendon  of  the  muscle  and  the  tendon  of  the  stylohyoid  muscle.  The  distance  at 
which  the  central  tendon  of  the  digastric  is  held  away  from  the  hyoid  bone  varies 
in  different  individuals  and  is  an  important  fact  to  bear  in  mind  in  searching  for 
the  artery.  If  the  tendon  rests  high  above  the  hyoid  bone  the  artery  must  be 
looked  for  low  down,  sometimes  even  under  the  tendon;  if,  on  the  contrary,  the 
tendon  is  low  down  the  artery  may  be  o.  5  to  i  cm.  higher  up.  The  hypoglossal  nerve 
lies  on  the  muscle  and  nearer  to  the  mandible  than  the  artery.  If  there  is  a  vein  on 
the  hyoglossus  muscle  it  is  apt  to  be  below  the  nerve,  that  is,  nearer  the  hyoid  bone, 
and  may  lie  directly  over  the  artery.  The  vein  and  the  nerve  are  to  be  displaced 
up  towards  the  jaw  and  an  incision  a  centimetre  long  made  through  the  hyoglossus 
muscle  a  short  distance  above  the  digastric  tendon  and  parallel  with  the  hyoid  bone. 
This  incision  should  not  be  deep,  as  the  muscle  is  only  2  or  3  mm.  (}i  in.)  thick. 


Middle  scalene  muscle 

Posterior  scalene  muscle 


Sternomastoid  muscle--  ^         ^  /       ,        i    \  -i  ^ 

^^       X  /  \  ^Omohyoid  muscle 

^    X       /      I      I    \  \ 

Phrenic 

Anterior  scalene  muscle  , 

Subclavian  vein  /  /  \  Suprascapular  artery  e 

Cords  of  brachial  ple.xus  /  Transverse  cervical  artery  and  veir 

Subclavian  artery 

Fig.  175. — Ligation  of  the  subclavian  artery 

The  edges  of  the  incision  being  raised  and  displaced  upward  and  downward,  the  artery 
will  probably  be  seen  running  at  right  angles  to  the  fibres  of  the  muscle  and  parallel  to 
the  hyoid  bone.  If  not  seen  at  once  it  should  be  looked  for  below  the  incision, 
nearer  to  the  hyoid  bone.  Care  must  be  taken  not  to  mistake  the  vein  for  the  artery. 
That  this  is  not  an  unlikely  thing  is  shown  by  its  occurring  in  the  hands  of  a  distin- 
guished surgeon  who  had  had  exceptional  experience  in  this  same  operation.  The 
ligature  needle  may  be  passed  from  above  downward  to  avoid  including  the  hypo- 
glossal nerve. 

Subclavian  Artery. — The  right  subclavian  artery  runs  from  the  sternoclavicular 
articulation  in  a  curved  hne  to  the  middle  of  the  clavicle.  It  rises  1.25  cm.  (J^  in., 
Walsham)  above  the  clavicle.  The  innominate  bifurcates  opposite  the  right  sterno- 
clavicular joint.  The  left  subclavian  springs  directly  from  the  arch  of  the  aorta, 
therefore  it  is  longer  than  the  right  by  4  to  5  cm.,  this  being  the  length  of  the  in- 
norninate.  As  the  subclavian  artery  passes  outward  it  is  crossed  by  the  scalenus 
anticus_  muscle,  which  divides  it  into  three  parts  :  the  first  part,  extending  to  the 
inner  side  of  the  muscle,  gi\'es  off  three  branches,  the  vertebral,  internal  mammary, 
and  thyroid  axis;  the  second  part,  behind  the  muscle,  gives  off  the  superior  intercos- 
tal; the  third  part  has  no  branches. 


148  APPLIED    AXATO-MY. 

The  first  port  io7i  of  the  subclavian  lies  very  deep  and  operations  on  it  have  been 
so  unsuccessful  that  they  have  been  practically  abandoned.  As  it  is  frequently 
in\olved  in  aneurisms  its  relations  are  worth  studying.  In  approaching  the  arter\- 
from  the  surface  it  is  seen  to  be  covered  by  the  sternomastoid,  the  sternohyoid, 
and  the  sternothyroid  muscles.  The  outer  edge  of  the  sternomastoid  muscle  corre- 
sponds with  the  outer  edge  of  the  scalenus  anticus.  The  three  first-named  muscles 
ha\"ing  been  raised,  the  arterj'  is  seen  to  be  crossed  by  the  internal  jugular,  the 
\'ertebral,  and  perhaps  the  anterior  jugular  veins.  The  anterior  jugular  above  the 
cla\icle  dips  beneath  the  inner  edge  of  the  sternomastoid  muscle  to  pass  outward 
and  empty  into  the  external  jugular  or  subclavian.  The  pneumogastric  nerve  crosses 
the  artery  just  to  the  inner  side  of  the  internal  jugular  \"ein.  Below,  the  artery  rests 
on  the  pleura,  and  on  the  right  side  the  recurrent  laryngeal  nene  winds  around  it.*. 
Behind  the  artery  are  the  pleura  and  lung,  which  rise  somewhat  higher  in  the  neck 
than  does  the  arterv. 

On  the  left  side  the  phrenic  nerve  leaves  the  scalenus  anticus  muscle  at  the  first 
rib,  crosses  the  subcla\-ian  at  its  inner  edge,  and  passes  down  on  the  pleura  to  cross 
the  arch  of  the  aorta.  To  the  inner  side  of  the  arterv  nans  the  thoracic  duct,  which, 
as  it  reaches  the  upper  portion  of  the  artery,  curves  over  it  to  cross  the  scalenus 
anticus  muscle  and  empty  into  the  junction  of  the  internal  jugular  and  subcla\'ian 
veins.  The  trachea  and  cesophag"us  are  likewise  seen  to  the  inner  side  of  the  artery. 
The  thvroid  axis  comes  off  its  anterior  surface,  the  vertebral  from  its  posterior,  and 
the  internal  mammary  below. 

The  second  po)i.ion  of  the  subclavian  aiioy  lies  behind  the  anterior  scalene 
muscle.  In  front  of  the  anterior  scalene  is  the  subclavian  vein.  The  phrenic  nerve 
runs  on  the  muscle  and  at  the  first  rib  lea\es  it  to  continue  down  between  the  right 
innominate  vein  and  pleura.  Behind  and  below,  the  artery  rests  on  the  pleura  and 
the  middle  scalene  muscle  is  to  its  outer  side.  Thus  it  is  seen  that  the  arterv  passes 
through  a  chink  formed  by  the  anterior  scalene  muscle  in  front  and  the  middle 
scalene  behind.  They  both  insert  into  the  first  rib.  The  posterior  scalene  is  farther 
back  and  inserts  into  the  second  rib.  Abo\-e  the  arter)^  are  all  the  cords  of  the 
brachial  plexus.  One  branch  of  the  subclavian,  the  superior  iyitcrcostal  artery,  is 
gi\en  off  near  the  inner  edge  of  the  anterior  scalene  muscle. 

The  third  portion  of  the  subclavian  runs  from  the  outer  edge  of  the  anterior  scalene 
muscle  to  the  lo\\'er  border  of  the  first  rib.  This  part  of  the  artery  is  the  most  super- 
ficial. The  only  muscle  co\'ering  it  abo\'e  is  the  thin  sheet  of  the  platysma,  lower 
down  the  subclavius  muscle  and  cla\ncle  overlie  it;  but  the  operations  on  the  vessel 
are  done  above  these  structures,  hence  they  do  not  interfere.  There  are  apt  to  be  a 
number  of  veins  in  front  of  the  artery.  The  e.xtemal  jugular  and  transverse  cervical 
veins  are  certain  to  be  present  and  perhaps  the  suprascapular  and  cephalic,  which 
ma\-  enter  above  instead  of  below  the  cla\"icle.  These  ^'eins  may  form  a  regular  net- 
work in  the  posterior  cervical  triangle  above  the  cla\'icle  and  pro\"e  x&xx  troublesome. 
Above  is  the  brachial  plexus  and  transverse  cervical  artery  and  still  higher  is  seen  the 
omohvoid  muscle.  The  suprascapular  artery  is  lower  down  and  usually  concealed 
just  below  the  upper  edge  of  the  clavicle.  The  lowest  cord  of  the  brachial  ple.xus, 
formed  by  the  first  dorsal  and  last  cervical  nerves,  may  be  posterior  to  the  artery. 
The  nerve  to  the  subclavius  muscle  passes  down  in  front  of  it. 

Ligation  of  the  Third  Potiion  of  the  Subclavian  Aiie?y. — The  head  is  to  be 
turned  strongly  to  the  opposite  side  and  the  shoulder  depressed.  This  lowers  the 
clavicle  and  raises  the  omohyoid  muscle  and  therefore  gi\'es  more  room  to  work. 
The  skin  is  to  be  drawn  down  and  an  incision  7.5  cm.  long  made  on  the  clavicle. 
The  drawing  down  of  the  skin  is  done  to  avoid  wounding  the  external  jugular  vein. 
This  vein  is  realh^  fastened  to  the  deep  fascia,  and  the  skin,  platysma,  and  super- 
ficial fascia  slide  over  it.  On  releasing  the  skin  it  slides  up  above  the  clavicle.  The 
middle  of  the  incision  should  be  a  little  to  the  inside  of  the  middle  of  the  clavicle. 
The  deep  fascia  is  to  be  incised  and  the  clavicular  origin  of  the  sternomastoid 
and  trapezius  muscles  cut  to  the  same  extent  as  the  superficial  incision.  The  length 
of  the  adult  male  clavicle  is  about  15  cm.  (6  in.). 

The  cla\icular  origin  of  the  sternomastoid  extends  out  on  the  clavicle  one-third 
of  its  length.     The  trapezius  inserts  into  the  outer  third.      This  leaves  the  middle 


THE   NECK.  149 

third  or  5  cm.  of  the  clavicle  on  its  upper  surface  free  from  muscles.  As  the 
incision  is  7.5  cm.  long  this  necessitates  the  division  of  2.5  cm.  (i  in.)  of  muscle, 
and  as  the  middle  of  the  incision  is  a  little  to  the  inner  side  of  the  middle  of  the 
clavicle  this  will  make  it  necessary  to  divide  more  of  the  clavicular  origin  of  the 
sternomastoid  than  of  the  trapezius.  After  the  division  of  the  deep  fascia,  fat  and 
veins  are  encountered.  The  scalenus  anticus  muscle  has  the  subclavian  vein  in 
front  of  it  and  the  artery  behind,  therefore  the  vein  must  be  attended  to  before  a 
search  is  made  for  the  edge  of  the  scalene  muscle.  The  veins  to  be  encountered  are 
the  external  jugular  vein,  which  empties  into  the  subclavian  in  front  of  or  to  the 
outer  side  of  the  anterior  scalene  muscle,  and  its  tributaries,  the  suprascapular  and 
transverse  cervical  veins,  as  well  as  the  anterior  jugular  and  a  communicating  branch 
from  the  opposite  side  of  the  neck.  The  cephalic  vein  not  infrequently  sends  a 
communicating  branch  over  the  clavicle  to  empty  into  the  external  jugular.  The 
fat  is  to  be  picked  away  with  forceps;  the  veins  are  to  be  held  out  of  the  way  with  a 
blunt  hook  or  ligated  and  cut.  The  suprascapular  artery  may  be  seen  close  to  or 
under  the  clavicle.  The  transverse  cervical  artery  may  perhaps  be  abo\'e  the  level 
of  the  wound.  The  omoh3'oid  muscle  may  or  may  not  be  seen,  as  its  distance  from 
the  clavicle  is  quite  variable.  The  transverse  cervical  and  suprascapular  arteries 
are  not  to  be  cut,  as  they  are  needed  for  the  collateral  circulation.  As  was 
mentioned  in  speaking  of  the  ligation  of  the  external  carotid  artery,  so  also  here  it 
is  not  always  easy  to  distinguish  between  arteries  and  veins.  The  veins  being 
disposed  of,  the  anterior  scalene  muscle  is  to  be  sought  at  the  internal  portion  of  the 
wound.  It  runs  somewhat  like  the  lower  portion  of  the  sternomastoid,  the  posterior 
edges  of  the  two  muscles  coinciding.  The  phrenic  nerve  runs  down  first  on  the 
anterior  surface  and  then  on  the  inner  surface  of  the  scalenus  anticus.  The  edge  of 
the  muscle  being  recognized,  by  following  it  down  the  finger  feels  the  first  rib.  The 
artery  lies  on  the  first  rib  immediately  behind  the  muscle  and  the  vein  immediately  in 
front  of  the  muscle.  The  tubercle  on  the  first  rib  may  not  be  readily  felt  because  the 
muscle  is  inserted  into  it.  The  prevertebral  fascia  coming  down  the  scalenus  anticus 
muscle  passes  from  it  to  the  subclavian  artery,  forming  its  sheath;  hence,  as  pointed 
out  by  George  A.  Wright,  of  Manchester  {Annals  of  Sm-gcry,  1S88,  p.  362  ),  the 
edge  of  the  muscle  may  not  readily  be  distinguished  and  the  brachial  plexus  is  a 
better  guide.  This  is  above  the  artery  and  the  lower  cord  of  the  plexus  lies  directly 
alongside  of  the  artery.  It  is  closer  to  the  artery  above  and  to  its  outer  side  than 
the  subclavian  vein  is  below  and  to  its  inner  side.  The  greatest  care  should  be 
exercised  in  passing  the  aneurism  needle  around  the  artery.  The  vein  is  not  so 
much  in  jeopardy  as  are  the  pleura  and  lowest  cord  of  the  brachial  plexus,  hence  the 
needle  is  passed  from  above  down  between  the  ner\-e  and  the  artery  and  brought 
out  between  the  artery  and  vein. 

Wounding  of  the  pleura  may  cause  collapse  of  the  lung  and  later  a  septic 
pleurisy,  while  including  the  nerve  will  cause  severe  pain,  etc. 

Collateral  Circnlaiion  after  Ligation  of  the  Third  Portion  of  the  Subclavian  Artery. 
— (i)  Internal  mammary  with  superior  thoracic  and  long  thoracic.  (2)  The  poste- 
rior scapular  branch  of  the  suprascapular  with  the  dorsalis  branch  of  the  subscap- 
ular. (3)  Acromial  branches  of  suprascapular  with  acromial  branch  of  acromial 
thoracic.  (4)  A  number  of  small  vessels  derived  from  branches  of  the  subclavian 
above  with  axillary  branches  of  the  main  axillary  trunk  below  (Gray). 

Ligation  of  the  Inferior  Thyroid  Artery. — The  inferior  thyroid  artery,  unlike 
the  superior,  lies  deep  from  the  surface,  and  it  is  a  far  more  difiicult  vessel  to  reach.  It 
is  a  branch  of  the  thyroid  axis,  the  other  branches  being  the  transverse  cervical  and 
suprascapular.  The  thyroid  axis  comes  from  the  first  part  of  the  subclavian  just  a 
little  to  the  inner  side  of  the  edge  of  the  scalenus  anticus  muscle.  The  inferior 
thyroid  artery  ascends  on  the  longus  colli  muscle,  just  to  the  inner  side  of  the 
scalenus  anticus  and  almost  in  front  of  the  vertebral  artery.  When  it  reaches  about 
the  level  of  the  seventh  cervical  vertebra  it  bends  inward  and  behind  the  carotid 
artery  to  reach  the  lower  posterior  edge  of  the  thyroid  gland.  The  transverse 
process  of  the  sixth  cervical  vertebra,  called  the  carotid  tubercle  of  Chassaignac,  is 
above  it.  As  it  bends  to  go  inward  it  gives  off  the  ascending  cer\'ical  artery.  In 
front  of  the  artery  are  the  internal  jugular  vein,  common  carotid  artery,  pneumo- 


15° 


APPLIED    ANATOMY. 


gastric  nerve,  and  the  middle  ganglion  of  the  sympathetic.  The  recurrent  laryngeal 
nerve  usually  passes  upward  behind  the  branches  of  the  artery  just  before  they  enter 
the  thyroid  gland.  The  thoracic  duct  on  the  left  side  passes  over  the  front  of  the 
artery  low  down. 

Operation.— hxi  incision  7.5  cm.  long  is  made  along  the  anterior  border  of  the 
sternomastoid  muscle,  extending  upward  from  the  clavicle.  This  will  bring  the  upper 
extremity  up  to,  or  even  above,  the  cricoid  cartilage.  The  anterior  jugular  vein 
will  have  to  be  ligated  and  the  muscle  displaced  outward.  The  common  carotid 
artery  should  then  be  isolated  and  it,  together  with  the  pneumogastric  nerve  and 
internal  jugular  vein,  drawn  outward.  The  omohyoid  muscle  may  appear  at  the 
upper  edge  of  the  incision.  Feel  for  the  carotid  tubercle  on  the  sixth  transverse 
cervical  process:  the  artery  lies  below  the  omohyoid  muscle  and  cricoid  cartilage  and 
below  the  tubercle  and  beneath  the  sheath  of  the  carotid.  If  the  trunk  of  the  sym- 
pathetic or  its  middle  cervical  gangHon,  which  lies  on  the  artery,  is  encountered,  it 


Profunda  cervicis 


Acromial  thorac 


Subscapul 
Dorsalis  scapul 


Long  thoracic 


Inferior  tiiyroid 
Common  carotid 
Vertebral 
Innominate 


Superior  intercostal 
Subclavian 
Superior  thoracic 
Internal  mammary 


Fig.  176. — Collateral  circulation  after  ligat: 


should  be  pushed  to  the  inner  side,  the  artery  isolated  outwardly  and  ligature  applied. 
Do  not  go  too  far  out  or  the  scalenus  anticus  will  be  reached  and  the  phrenic  nerve 
may  be  injured,  nor  too  far  in,  to  avoid  wounding  the  recurrent  laryngeal. 

The  thyroidea  ivia  {inferior  thyroid)  veins  do  not  cross  outward  nor  accompany 
the  artery,  but  proceed  downward  on  the  trachea  to  empty  into  the  innominate  veins. 


THE  CERVICAL  FASCIAS. 

There  are  two  fascias  in  the  neck,  the  superficial  and  the  deep.  The  super- 
ficial fascia  has  blended  with  it  anteriorly  the  platysma  muscle  and  the  termination  of 
the  nerves,  arteries,  and  veins.  The  main  trunks  of  these  structures  lie  for  all 
practical  purposes  beneath  the  superficial  fascia  and  adherent  to  the  surface  of  the 
deep  fascia.  It  is  for  this  reason  that  in  raising  the  superficial  structures  the  larger 
trunks  remain  applied  to  the  deep  fascia  and  are  thus  less  liable  to  be  injured  in  the 
living  and  mutilated  in  the  dead.  In  the  superficial  fascia  and  on  the  deep  fascia  are 
the  superficial  lymphatics. 


THE    NECK. 


151 


The  superficial  lymphatic  nodes  frequently  suppurate.  When  they  do  the 
abscess  so  formed  is  prevented  by  the  deep  fascia  from  reaching  the  parts  beneath,  so 
the  pus  works  its  way  out  through  the  skin.  As  the  superficial  fascia  is  loose,  if 
the  abscess  is  slow  in  formation,  it  may  extend  for  a  considerable  distance  under  the 
skin. 

Sebaceous  cysts  are  common  in  the  neck.  As  they  are  superficial  to  the  deep 
fascia,  which  is  not  involved,  they  can  be  removed  without  fear  of  wounding  any 
important  structures.  The  veins  do  not  overlie  them;  they  are  always  superficial 
to  the  veins,  therefore  there  is  no  danger  of  wounding  the  external  jugular. 

The  Deep  Cervical  Fascia. — The  deep  cervical  fascia  completely  envelops 
the  neck  and  sends  its  branches  in  between  all  its  various  structures.  It  is  the 
fibrous  tissue  that  both  unites  and  separates  all  the  different  structures  to  and  from 
each  other.  Where  this  fascia  is  abundant  it  forms  a  distinct  layer,  but  where  it  is 
scant  it  is  simply  a  small  amount  of  connective  tissue  between  two  adjacent  parts. 


Superficial  layer  of  deep  cerv  ical  fascii 

Pretricheal  Hjer  ^  > 
Cricoid  cartilage.^ 
Cncothyroid  muscle 
Pre\  ertebral  la>  er 
Loogus  colli 


Trachelomastoid 


Sternohyoid  muscle 
Sternothyroid 
'  Thjroid  i,land 
/     Ojiiohyoid 


Sixth  vertebra 


Multifidus  spin, 
Semispinales  cervices 

Fig.  177. — Transverse  section  of  the  neck  through  the  sixth  cervical  vertebra. 

To  follow  all  the  processes  of  the  deep  fascia  through  the  neck  between  its  innumer- 
able structures  is  impossible — nor  is  it  necessary.  The  main  reason  for  studying  the 
deep  cervical  fascia  and  its  various  parts  is  to  understand  the  course  pursued  by 
abscesses  and  infections.  This  is  best  done  by  limiting  oneself  to  the  main  super- 
ficial layer  and  some  of  the  larger  layers  crossing  from  side  to  side. 

The  principal  layers  of  the  deep  cervical  fascia  are  the  superficial  layer,  which 
completely  encircles  and  envelops  the  neck,  the  prevertebral  layer,  which  passes 
from  side  to  side  in  front  of  the  spinal  column,  and  the  pretracheal  layer,  which  passes 
from  side  to  side  in  front  of  the  trachea. 

The  Superficial  Layer. — The  superficial  layer  of  the  deep  fascia  envelops  the 
whole  of  the  neck,  with  the  exception  of  the  skin,  platysma,  and  superficial  fascia. 
It  is  attached  above  to  the  occipital  protuberance,  the  superior  curved  line  of  the  occi- 
put, the  mastoid  process,  then  blends  with  the  capsule  of  the  parotid  gland,  then  passes 
to  the  angle  of  the  jaw  and  along  the  body  of  the  mandible  to  the  symphysis, 
whence  it  proceeds  around  the  opposite  side  in  the  same  manner.  Below  it  is 
attached  to  the  sternum,  upper  edge  of  the  clavicle,  acromion  process,  and  spine  of 
the  scapula,  thence  across  to  the  vertebral  spines,  to  which  and  to  the  ligamentum 


152  APPLIED    ANATOMY. 

nuchae  it  is  attached  up  to  the  occipital  protuberance.  In  the  front  of  the  neck  it 
passes  from  the  mandible  down  to  be  attached  to  the  hyoid  bone  and  thence  down- 
ward to  the  sternum  and  clavicle. 

From  the  under  side  of  this  superficial  layer  processes  of  fascia  come  off  and 
envelop  the  various  structures  of  the  neck.  E\'ery  separate  structure  of  the  neck 
is  co\'ered  by  it  and  therefore  separated  from  the  adjacent  parts  b\'  a  more  or  less  dis- 
tinct layer  of  the  fascia.  In  many  places  it  is  quite  thin  or  almost  imperceptible, 
amounting  to  but  a  few  shreds  of  fibrous  tissue,  in  other  places  it  is  more  distinct, 
forming  more  or  less  marked  capsules,  as  in  the  case  of  the  thj'roid  and  submaxillary 
glands,  or  fibrous  layers,  as  in  the  case  of  those  in  front  of  the  vertebrae  and  trachea. 
Posteriorly  in  the  median  line  the  superficial  layer  of  the  deep  fascia  sends  a  process 
which  covers  the  under  surface  of  the  trapezius  muscle.  Anteriorly  another  process 
is  given  off  to  cover  the  under  surface  of  the  sternomastoid  muscle.      The  super- 


-Prevertebral  fascia 
-Pneumogastric  nerve 
-Common  carotid  artery 
-Internal  jugular  vein 
-Sheath  of  the  vessels 

-Superficial  layer  of  deep  fascia 
-CEsophagus 


Fig.  1-8. — Deep  cervical  fascia.     The  pharynx  and  larynx  have  been  cut  away,  exposing  the  prevertebral  and 

pretracheal  layers. 

ficial  veins  of  the  neck,  the  anterior,  external,  and  posterior  jugulars,  lie  on  or  in 
the  deep  fascia,  being  stuck  to  or  blended  with  its  upper  surface. 

About  3  cm.  (i}^  in.)  above  the  sternum  the  deep  fascia  splits  into  two  layers, 
one  to  be  attached  to  the  anterior  and  the  other  to  the  posterior  edge  of  the  sternum 
in  front  of  the  sternohyoid  and  sternothyroid  muscles.  Between  these  two  layers  is 
the  space  of  Burns ;  it  contains  the  lower  ends  of  the  anterior  jugular  veins  with 
the  branch  that  joins  them,  some  fatty  tissue  and  lymphatic  nodes,  and  the  sternal 
origin  of  the  sternomastoid  muscle.  Sometimes  a  vein  comes  up  from  the  surface  of 
the  chest  below  to  open  into  the  anterior  jugular  vein. 

The  prevertebral  layer  passes  from  side  to  side  directly  on  the  bodies  of  the 
vertebrffi.  It  covers  the  muscles  attached  to  the  spine,  as  the  scalene,  longus  colli, 
rectus  capitis  anticus,  and  also  the  nerves,  as  those  of  the  brachial  plexus,  coming 
from  the  spine.  On  reaching  the  carotid  artery  and  jugular  vein  it  helps  to  form 
their  sheath.  Its  upper  edge  is  attached  to  the  base  of  the  skull  at  the  jugular  fora- 
men and  carotid  canal  and  thence  across  the  basilar  process  to  the  opposite  side. 
Inferiorly  it  passes  down  on  the  surface  of  the  bodies  of  the  vertebrse  into  the  pos- 
terior mediastinum. 


THE   NECK.  153; 

From  the  sheath  of  the  vessels  outward,  beyond  the  posterior  edge  of  the  sterno- 
mastoid  muscle,  the  prevertebral  fascia  covers  the  scalene  muscles,  the  brachial  plexus 
of  nerves,  and  the  subclavian  artery.  On  reaching  the  clavicle  the  fascia  is  attached 
to  its  upper  surface,  blending  with  the  superficial  layer;  it  is  then  continued  down 
over  the  subclavian  muscle,  forming  its  sheath,  and  ends  as  the  costocoracoid  mem- 
brane. The  part  over  the  subclavian  artery  and  vein  is  continued  over  them  and 
the  brachial  plexus  and  follows  them  into  the  axilla.  This  fascia  forms  the  floor  of 
the  posterior  cervical  triangle;  the  roof  is  formed  by  the  superficial  layer  of  the  deep 
fascia.  It  is  between  these  layers  that  the  suprascapular  artery  and  veins  run.  The 
descending  branches  of  the  cervical  plexus,  the  spinal  accessory  nerve,  omohyoid 
muscle,  and  some  fat  and  lymph-nodes  are  also  found  there. 

'Wi^  pretracheal  layer  passes  from  side  to  side  in  front  of  the  trachea.  Laterally 
it  too  blends  with  the  sheath  of  the  vessels  and  is  continued  posteriorly  behind  the 
pharynx  and  cesophagus  as  the  buccopharyngeal  fascia.  In  front  it  blends  in  the 
median  line  with  the  superficial  layer  and  is  attached  to  the  hyoid  bone  and  cricoid 
cartilage.  It  splits  to  enclose  and  form  a  capsule  for  the  thyroid  gland,  and  below  en- 
closes in  its  meshes  the  inferior  thyroid  veins,  and  thence  passes  to  the  arch  of  the 
aorta  to  be  continuous  with  the  pericardium.  Laterally  it  passes  under  the  sterno- 
hyoid, omohyoid,  and  sternothyroid  muscles  to  blend  with  the  sheath  of  the  vessels 
and  the  layer  on  the  posterior  surface  of  the  sternomastoid  muscle.  This  is  its 
lateral  limit.  Underneath  the  sternomastoid  muscle  a  loop  of  fascia  proceeds  down- 
ward from  the  omohyoid  muscle  to  the  first  rib.  This  is  derived  from  the  sheath 
of  the  vessels  beneath  and  the  layer  on  the  under  surface  of  the  sternomastoid 
superficially. 

The  sheath  of  the  vessels  envelops  the  carotid  artery,  jugular  vein,  and  pneumo- 
gastric  nerve.  Thin  layers  of  fascia  pass  between  these  structures,  separating  one 
from  the  other.  The  sheath  is  formed  by  the  union  of  the  outer  edge  of  the  pre- 
tracheal fascia  and  the  prevertebral  fascia,  with  the  fascia  lining  the  under  surface  of 
the  sternomastoid  muscle.  This  sheath  follows  the  vessels  down  into  the  chest  and 
out  into  the  a.xilla. 

The  capsule  of  the  parotid  gland  is  formed  by  the  splitting  of  the  superficial 
layer  of  the  deep  cervical  fascia  as  it  passes  from  the  mastoid  process  to  the  angle  of 
the  jaw.  Its  superficial  portion  is  attached  to  the  zygomatic  process.  Its  deep  por- 
tion passes  from  the  styloid  process  to  the  angle  of  the  jaw  and  is  known  as  the 
stylomandibular  ligament. 

The  capsule  of  the  submaxillary  gland  is  formed  by  a  splitting  of  the  superficial 
layer  at  the  hyoid  bone.  It  forms  the  covering  of  the  gland  and  from  the  hyoid 
bone  sends  a  process  upward  which  lies  on  the  digastric  and  mylohyoid  muscles 
and  follows  the  latter  up  to  be  attached  along  the  mylohyoid  ridge  of  the  mandible. 
It  proceeds  with  the  submaxillary  gland  around  the  posterior  edge  of  the  mylohyoid 
muscle  to  cover  its  upper  surface.  The  stylomandibular  ligament  alluded  to  above 
separates  the  parotid  from  the  submaxillary  gland. 

The  capsule  of  the  thyroid  gland  is  not  very  thick  and  the  gland  is  readily 
separated  from  it,  as  is  also  the  case  with  the  submaxillary  gland.  It  is  continued 
downward  in  front  of  the  trachea  as  the  pretracheal  layer  and  laterally  it  blends  with 
the  sheath  of  the  vessels.  It  follows  the  vessels  downward  into  the  chest  and  is 
continuous  with  the  pericardium.  The  ^-eins  of  the  gland,  which  are  at  times  very 
large,  run  beneath  the  capsule  and  bleed  freely  if  wounded. 

The  Buccopharyngeal  Fascia. —  Between  the  pharynx  in  front  and  the  ver- 
tebral column  behind  is  the  retropharyngeal  space.  The  fascia  forming  the  pos- 
terior wall  of  this  space  is  the  prevertebral  fascia  already  described.  Forming  its 
anterior  wall  is  a  thin  layer  of  connective  tissue  called  the  buccopharyngeal  fascia. 
It  invests  the  superior  constrictor  of  the  pharynx  and  is  continued  forward  on  the 
buccinator  muscle.  It  is  continued  downward  behind  the  pharyn.x  and  oesophagus 
into  the  posterior  mediastinum:  laterally  it  blends  with  the  sheath  of  the  vessels 
and  is  continuous  with  the  pretracheal  fascia  around  the  larynx,  trachea,  and  thyroid 
gland  (Fig.  179). 

Abscesses  of  the  Neck. — Abscesses  of  the  neck  usually  arise  in  connection 
with   the  lymphatic  nodes.     They  may  also   start  from    infected  wounds,    carious 


154 


APPLIED    ANATOMY. 


teeth,  suppuration  of  the  thyroid  gland,  and  other  causes.  They  may  ha\e  their 
course  influenced  by  the  various  layers  of  the  deep  fascia. 

Ptis  in  the  Submaxillary  Region.— As  the  submaxillary  space  has  the  mylo- 
hyoid muscle  as  its  floor,  abscesses  here  show  below  the  body  of  the  mandible 
between  it  and  the  hyoid  bone.  Usually  they  point  towards  the  skin.  Infection  of 
this  space  may  occur  from  the  teeth.  Tillmans  ("Surgery,"  vol.  i,  p.  434)  saw  a 
case  in  which  in  four  days  the  pus  caused  death  from  infection  of  the  mediastinum 
and  pleura.  This  proceeded  downward  from  a  badly  extracted  tooth  and  thence 
under  the  deep  fascia  of  the  neck  to  the  chest. 

The  pus,  filling  the  submaxillary  space,  as  can  also  occur  in  Ludwig's  angina, 
which  is  an  infective  inflammation  of  the  submaxillary  and  sublingual  regions,  may 
follow  the  lingual  and  facial  arteries  to  the  sheath  of  the  great  vessels  and  down  into 
the  superior  mediastinum.  The  infection  in  Ludwig's  angina  may  pass  around 
the  posterior  edge  of  the  mylohyoid  muscle  and  involve  the  structures  around  the 


Internal  pterygoid 


Buccopharynfieal  _ 


Prevertebral  fasci 


Fig.  179= — Secti 


External  carotid  artery 


Vagu 
Internal  carotid  artery 

ugh  the  upper  portion  of  the  third  cervical  vertebra,  showing  the  buccophar^Tigeal 
prevertebral  fascias  and  retropharyngeal  space. 


base  of  the  tongue  and  pharynx,  and  produce  cedema  of  the  larynx  and  death  (see 
page  200). 

Pics  superficial  to  the  deep  fascia  tends  to  perforate  the  skin  and  discharge 
externally.  If  it  is  slow  in  forming  it  may  sink  down  and  pass  over  the  clavicle 
onto  the  upper  portion  of  the  chest. 

Pus  in  the  sup7'aste7nial  notch  or  space  of  Burns  bulges  anteriorly  but  may 
perforate  posteriorly.  The  sternothyroid  and  sternohyoid  muscles  are  attached  to  the 
posterior  surface  of  the  sternum;  but  the  layer  of  fascia  on  their  anterior  surface  is 
very  thin,  so  that  pus  may  either  pass  between  the  muscles  or  perforate  them  and  so 
pass  down  in  front  of  the  pretracheal  fascia  close  to  the  under  surface  of  the  sternum. 
It  would  then  tend  to  show  itself  in  the  upper  intercostal  spaces,  close  to  the 
sternum. 

Pus  between  the  pretracheal  and  superficial  layers,  as  may  occur  from  abscesses 
of  the  thyroid  gland,  tends  to  work  its  way  downward  rather  than  laterally.  The 
pretracheal  fascia  at  the  sides  blends  with  the  sheath  of  the  vessels  and  the  fascia 
covering  the  posterior  surface  of  the  sternomastoid  muscles.  In  this  space  lie  the 
sternohyoid,  sternothyroid,  and  omohyoid  muscles.  The  pretracheal  fascia  is  beneath 
them  and  the  superficial  layer  of  the  deep  fascia  above.      Pus  can  follow  the  posterior 


THE    NECK. 


I5S 


surface  of  these  muscles  down  behind  the  sternum  in  front  of  the  innominate  veins 
and  arch  of  the  aorta. 

Pus  between  the  pretracheal  and  prevertebral  layers  cannot  go  further  to  one 
side  than  the  sheath  of  the  vessels.  Therefore  it  follows  the  trachea  and  oesophagus 
down  into  the  posterior  mediastinum.  This  space,  between  these  layers,  is  some- 
times called  the  visceral  space  because  it  contains  the  oesophagus,  trachea,  and 
thyroid  gland.  Pus  in  this  space  can  also  perforate  into  the  trachea,  pharynx, 
oesophagus,  or  even  extend  laterally  and  involve  the  great  vessels. 

If  the  anterior  portion  of  the  thyroid  gland  suppurates,  the  pus  may  perforate  the 


Pretracheal  layer 
Cricoid  cartilage 


Prevertebral  layei 
Cricoid  cartilage 


Left  innominate 


The  superficial  layer,  pretracheal  layer,  and  prevertebral  layer  of  the  deep  ( 


thin  pretracheal  fascia  covering  it  and  pass  down  behind  the  sternohyoid  and  sterno- 
thyroid muscles  into  the  anterior  part  of  the  superior  mediastinum. 

Pus  posterior  to  the  prevertebral  fascia,  as  from  caries  of  the  \'ertebrae,  if  high 
up  may  bulge  into  the  pharynx,  forming  a  retropharyngeal  abscess.  It  may  follow 
the  scaleni  muscles  and  brachial  plexus  down  around  the  axillary  artery  into  the 
axilla.  In  the  neck  it  shows  itself  posterior  to  the  carotid  arteries  and  to  the  outer 
edge  of  the  sternomastoid  muscles. 

Pus  in  the  sheath  of  the  great  vessels,  when  originating  from  lymphatic  nodes, 
may  first  raise  the  sternomastoid  muscle  and  show  itself  along  its  anterior  border; 
it  may  perforate  the  lumen  of  the  vessels;  it  may  pass  down  with  the  vessels  into  the 
superior  mediastinum;  or  it  may  bulge  into  the  visceral  space  between  the  pre- 
vertebral and  pretracheal  layers  and  follow  the  trachea  and  oesophagus  down  into  the 
chest.  Should  it  tend  outwardly  it  may  break  into  the  posterior  cervical  triangle 
between  the  prevertebral  and  superficial  layers  and  show  itself  above  the  clavicle. 


156  APPLIED    ANATOMY. 

Retrophaiyngeal  Abscess. — Pus  which  tends  to  point  into  the  pharynx  may  come 
from  disease  of  the  vertebrae,  in  which  case  it  is  posterior  to  the  pre^-ertebral  fascia : 
or  it  may  originate  from  the  lymphatic  nodes  in  the  retrophar^mgeal  space. 

When  coming  from  caries  of  the  Aertebrae,  it  may  point  either  in  the  phar\-n.\ 
or,  pushing  its  way  outward,  pass  behind  the  great  vessels  and  show  itself  behind 
the  outer  edge  of  the  sternomastoid  muscle.  I  have  seen  it  point  in  both  these 
places  in  the  same  case.  When  originating  in  the  retropharyngeal  space  it  lies  in 
front  of  the  pre\'ertebral  fascia  and  behind  the  buccopharvngeal  fascia.  It  either 
points  forward  into  the  pharynx  qr,  going  down,  follows  the  posterior  surface  of  the 
oesophagus  into  the  posterior  mediastinum.  It  may  also  perforate  the  oesophagus 
and  enter  its  lumen. 

Pus  in  the  Posterior  Cervical  Triangle. — If  abo\-e  the  pre\-ertebral-  la-\-er  this 
bulges  directly  for^vard  and  tends  to  open  through  the  skin.  Its  progress  downward 
is  obstructed  by  the  attachment  of  the  superficial  layer  to  the  top  ol  the  clavicle  as 
it  blends  with  the  prevertebral  layer.  If  pus  is  beneath  the  prevertebral  layer  it  may 
then  follow  tlie  brachial  plexus  and  subclavian  artery  down  beneath  the  cla\-icle  and 
appear  in  the  axilla.  The  attachments  of  the  costocoracoid  membrane  tend  to  direct 
the  pus  laterally  under  the  pectoralis  minor  muscle  into  the  axilla  rather  than  to  allow 
it  to  come  forward  on  the  anterior  portion  of  the  chest. 

LYMPHATICS  OF  THE  NECK. 

The  lymphatics  of  the  neck  are  both  superficial  and  deep.  The  superficial 
nodes  communicate  freely  with  and  end  in  the  deep  ones.  For  the  sake  of  conven- 
ience we  may  di\-ide  them  into  a  transverse  set,  embracing  the  subniejital,  submaxillary, 
S7iperficial  upper  cervical  (behind  the  angle  of  the  ia-\\-),  posterior  auricular,  and 
occipital  nodes;  and  two  longitudinal  sets,  one  along  the  great  vessels  and  another,  a 
posterior  set,  in  the  posterior  cervical  triangle. 

The  Transverse  Lymphatics. — The  stcbmenial  nodes,  also  called  the  supra- 
hyoid, lie  beneath  the  chin  and  drain  the  region  of  the  lower  lip  and  chin  and  anterior 
part  of  the  floor  of  the  mouth.  These  will  be  enlarged  in  children  with  ulcerative  skin 
affections  of  these  regions.  They  may  also  be  in\-olved  in  carcinoma  of  the  lower  lip, 
especially  if  near  the  median  line.  That  the  submental  nodes  drain  the  tissues  of  the 
anterior  portion  of  the  mouth  and  probably  the  tongue  itself  is  shown  by  Henry  T. 
Butlin  ("Surgery  of  Malignant  Disease,"  p.  153),  who  states  that  the  submental 
nodes  are  frequently  affected  in  carcinoma  of  the  tongue  when  its  tip  is  involved. 

The  submaxillary  nodes  are  beneath  the  body  of  the  mandible  in  the  sub- 
maxillary triangle.  They  drain  the  lips,  nose,  floor  of  the  mouth,  gums,  anterior 
portion  of  the  tongue  and  side  of  the  face.  These  are  the  nodes  most  frequently 
affected  in  carcinomatous  affections  of  the  lips  and  anterior  portion  of  the  tongue. 
Henr}'  T.  Butlin  ("Surgery  of  Malignant  Disease,"  p.  153)  calls  attention  to  the 
fact  that  in  malignant  disease  of  one  side  of  the  anterior  portion  of  the  tongTie  the 
lymphatics  of  the  opposite  side  may  also  be  in-\-olved,  thus  showing  that  the  lym- 
phatics of  the  two  sides  of  the  tongue  freely  anastomose.  This  is  contrary  to  what 
exists  as  regards  the  arteries,  which  anastomose  hardly  at  all  across  the  median  line. 
He  also  states  that  one  or  more  of  the  lymphatic  nodes  is  frequently  imbedded  in  the 
substance  of  the  submaxillary  gland.  Therefore  the  submaxillary  gland  is  excised  at 
the  same  time  as  the  affected  lymphatic  nodes. 

The  superficial  upper  cervical  {subparotid)  nodes  are  just  belo«-  the  parotid 
lymphatics  and  behind  the  angle  of  the  jaw.  They  drain  the  region  embraced  by 
the  masseter  muscle  as  far  back  as  the  ear.  They  may  be  enlarged  in  affections  of 
the  skin  and  scalp  above.  Therefore  in  children  with  enlargement  of  these  nodes 
the  source  of  infection  should  be  sought  in  those  regions. 

The  posterior  auricular  nodes  are  behind  the  ear  on  the  mastoid  process  and 
insertion  of  the  sternomastoid  muscle.  In  practice  thev  are  encountered  as  small 
( I  cm. ),  round  swellings  behind  the  ear,  which  are  usually  quite  tender  to  the  touch. 
This  is  probably  due  to  their  being  placed  on  a  hard,  bony  base.  When  enlarged 
they  are  often  the  subject  of  operations. 


THE   NECK. 


157 


The  superficial  occipital  nodes  are  just  below  the  superior  curved  Hne  of  the 
occiput  or  a  Httle  lower  down  in  the  hollow  below  the  occiput  between  the  posterior 
edge  of  the  sternomastoid  and  anterior  edge  of  the  trapezius  muscles,  resting  on  the 
splenius.  These  are  the  nodes  that  are  enlarged  in  syphilis  and  are  to  be  searched 
for  in  endeavoring  to  establish  a  diagnosis. 

Superficial  and  Deep  Abodes.  —  The  five  sets  of  nodes  just  described,  viz. ,  the 
submental,  submaxillary,  superficial  upper  cervical,  posterior  auricular,  and  superficial 
occipital,  are  all  regarded  as  superficial  nodes.  As  a  matter  of  fact  this  division  of  the 
lymphatic  nodes  into  superficial  and  deep  is  not  of  practical  value.  The  communica- 
tion between  the  various  nodes  is  quite  free.  Adjacent  nodes  communicate  and  the 
superficial  nodes  communicate  with  the  deep  ones  below. 

On  account  of  this  an  affection  is  not  always  limited  to  a  single  node  but  often 
involves  those  to  each  side  and  those  lying  still  deeper.      In  the  submaxillary  region 


Fig.  181. — Superficial  lymphatic  vessels 


3  of  head  and  neck: 


lidiacrammatic.    (Piersol.) 


the  nodes  will  almost  certainly  be  found  to  lie  under  the  fascia  along  with  the  sub- 
maxillary gland.  When  the  occipital  nodes  are  enlarged  they  may  not  only  be 
found  in  the  space  already  described  but  also  on  the  adjacent  trapezius  and  sterno- 
mastoid muscle  and  even  beneath  the  outer  edge  of  the  trapezius  below  the  deep 
fascia. 

The  Longitudinal  Lymphatics. — These  are  along  the  great  -^-essels, — the 
anterior  cervical  lymphatics, — and  in  the  posterior  cervical  triangle. 

The  anterior  cervical  lymphatics  is  the  name  given  to  those  which  tend  to  show 
in  the  anterior  cervical  triangle  either  beneath  or  in  front  of  the  sternomastoid 
muscle,  between  it  and  the  median  line.  There  are  some  nodes  in  the  median  line 
but  they  are  almost  all  deep  down  in  the  neck  above  the  sternum.  The  other  nodes 
may  be  either  superficial  or  deep,  mostly  deep,  along  the  edge  of  the  sternomastoid 


158  APPLIED    ANATOMY. 

muscle.  They  follow  the  sheath  of  the  vessels.  This  is  a  very  extensive  chain  of 
nodes.  They  may  e.xtend  in  all  directions.  As  regards  depth  they  may  be  on  the 
deep  fascia  along  the  edge  of  the  sternomastoid  or  following  the  external  jugular 
vein.  If  deeper  they  follow  the  internal  jugular  vein  and  carotid  artery  directly 
up  to  the  base  of  the  skull,  also  behind  and  below  the  mastoid  process  and  along- 
side of  the  transverse  process  of  the  atlas  (first  cervical  vertebra).  They  extend 
under  the  sternomastoid  posteriorly,  deep  in  the  suboccipital  region.  Should 
they  be  enlarged  downward  they  will  protrude  behind  the  posterior  edge  of  the 
sternomastoid  into  the  posterior  cervical  triangle;  if  anteriorly  they  will  follow  it 
down  into  the  space  of  Burns  in  front  of  the  trachea  and  thence  into  the  superior 
mediastinum. 

The  postei'ior  cej-vical  nodes  show  behind  the  posterior  edge  of  the  sternomastoid, 
along  the  edge  of  the  trapezius,  and  also  above  the  cla\icle.  They  not  infrequently 
fill  the  posterior  cervical  triangle  and  extend  beneath  the  muscles  on  each  side. 

Below  they  may  be  continuous  with  enlarged  nodes  in  the  axilla  and  extend 
anteriorly  under  the  sternomastoid  into  the  pretracheal  region  and  mediastinum. 
They  are  frequently  excised  for  both  tuberculosis  and  carcinoma.  In  so  doing 
particular  care  is  to  be  taken  on  account  of  the  trans^'ersalis  colli  and  suprascapular 
arteries  and  veins,  with  which  they  may  lie  in  contact,  as  well  as  the  terminal  por- 
tion of  the  external  jugular. 

Postpharyngeal  Nodes. — In  the  retropharyngeal  space,  toward  the  sides, 
between  the  buccopharyngeal  fascia  in  front  and  the  prevertebral  fascia  behind  are 
located  one  or  two  nodes  (see  buccopharyngeal  fascia,  page  153,  and  retropharyn- 
geal abscess,  page  156).  They  seem  to  be  the  starting  point,  sometimes,  of  retro- 
pharyngeal abscess.  They  do  not  appear  to  get  enlarged  and  project  into  the 
pharyn.x  as  tumors,  as  might  be  expected,  so  tliat  they  are  not  subjected  to  any 
surgical  procedures. 

Operating  for  the  Removal  of  Enlarged  Cervical  Nodes. — This  opera- 
tion may  be  one  of  the  most  serious  in  surgery.  Sir  Frederick  Treves  says  :  "  An 
operation  of  this  kind  should  not  be  undertaken  unless  the  surgeon  has  perfect  con- 
fidence in  his  practical  knowledge  of  the  anatomy  of  the  neck.  Scarcely  an  instance 
can  be  cited  in  the  range  of  operative  surgery  where  a  knowledge  of  the  structure 
and  of  relations  is  more  essential  than  in  these  excisions. ' '  The  main  difficulties 
encountered  are  in  the  avoidance  of  nerves  and  the  control  of  hemorrhage.  Air 
may  enter  the  veins  and  cause  death,  and  the  thoracic  duct  may  be  wounded.  The 
latter  accident  sometimes  results  fatally.  The  difficulty  of  the  operation  will  de- 
pend on  the  size  and  number  of  the  nodes,  their  location,  and  the  character  of  the 
inflammation  or  other  changes  they  have  undergone.  In  an  early  stage  the  nodes 
may  be  lying  loose  in  the  tissues  and  can  be  readily  turned  out  when  once  exposed. 
Later  they  may  be  matted  to  the  surrounding  structures  by  inflammatory  deposits 
and  then  their  separation  is  a  matter  of  difficulty  and  danger. 

The  skin  incisions  may  be  either  longitudinal  or  more  or  less  transverse.  The 
longitudinal  incisions  are  usually  along  either  the  anterior  or  posterior  border  of 
the  sternomastoid  muscle,  or  the  anterior  edge  of  the  trapezius.  The  transverse 
incision  may  be  either  opposite  the  hyoid  bone — when  it  may  be  prolonged  around 
the  angle  of  the  jaw  and  up  to  the  mastoid  process  and  over  the  suboccipital  glands, 
or  above  the  clavicle. 

As  the  skin  and  superficial  structures  are  cut  and  the  deep  fascia  opened, 
the  superficial  veins  will  be  cut,  hence  the  first  anatomical  fact  to  be  borne  in  mind 
is  the  probable  location  of  the  veins.  The  most  important  of  these  is  the  external 
jugular.  The  internal  jugular  below  the  hyoid  bone  lies  under  the  sternomastoid 
muscle  and  therefore  is  protected  until  the  deeper  dissection  is  begun.  The  external 
jugular  runs  about  in  a  line  from  the  angle  of  the  jaw  to  the  middle  of  the  posterior 
edge  of  the  sternomastoid  muscle  and  thence  downward  to  about  the  middle  of  the 
clavicle.  Therefore  an  incision  along  the  posterior  edge  of  the  sternomastoid  will 
divide  it  at  about  the  middle  of  the  muscle,  and  the  surgeon  should  be  prepared  to 
guard  against  an  undue  loss  of  blood  when  it  is  cut.  Opening  into  the  external 
jugular  posteriorly  between  the  middle  of  the  sternomastoid  muscle  au'd  the  clavicle 
below  are  the  posterior  jugular,  the  transverse  cervical,  and  the  suprascapular  veins. 


THE    NECK.  159 

These  latter  open  into  the  external  jugular  i  or  2  cm.  above  the  clavicle  and  are 
almost  certain  to  be  cut  in  operations  in  the  supraclavicular  fossa.  An  incision 
along  the  anterior  edge  of  the  sternomastoid  low  down  will  cut  the  anterior  jugular 
vein  a  short  distance  above  the  sternum  as  it  winds  beneath  the  sternomastoid  to 
empty  into  the  external  jugular.  An  incision  along  the  anterior  border  of  the 
sternomastoid  from  its  middle  up  is  bound  to  cause  free  hemorrhage.  The  external 
jugular  behind  the  angle  of  the  jaw  communicates  with  the  facial,  which  empties  into 
the  internal  jugular;  hence  division  of  the  external  jugular  at  this  point  also  drains 
the  blood  almost  directly  from  the  internal  jugular.  A  carelessly  deep  incision  may 
wound  the  internal  jugular  itself  in  the  region  posterior  to  the  hyoid  bone.  The 
internal  jugular  is  more  superficial  at  this  point  than  it  is  lower  down.  The  temporo- 
ma.\illary  and  posterior  auricular  veins  will  also  be  cut  behind  the  ramus  of  the  jaw. 

Not  only  are  veins  cut  but  also  nerves.  The  middle  of  the  posterior  edge 
of  the  sternomastoid  is  the  point  of  departure  of  several  nerves.  The  superficial 
cervical  runs  directly  transversely  inward  toward  the  thyroid  cartilage.  The  auricu- 
laris  magnus  goes  up  to  the  lobe  of  the  ear,  and  the  occipitahs  minor  follows  the 
posterior  edge  of  the  muscle  up  to  the  occiput.  These  three  nerves  are  nerves  of  sen- 
sation and  if  they  are  divided  only  a  certain  amount  of  temporary  anaesthesia  will  be 
produced  over  the  parts  they  supply,  hence  their  division  is  not  a  matter  of  much 
moment.  The  auricularis  magnus  is  the  largest  of  the  three.  The  descending 
branches  of  the  cervical  plexus,  which  leave  the  posterior  edge  of  the  sternomastoid 
muscle  immediately  below  the  nerves  just  mentioned,  proceed  down  under  the  deep 
fascia  and  will  be  seen  only  in  a  deeper  dissection.  The  nerve  which  it  is  absolutely 
important  to  avoid  is  the  spinal  accessory.  This  enters  the  sternomastoid  muscle 
on  its  under  surface  some  little  distance  back  of  its  anterior  edge  and  3  to  5  cm. 
below  the  mastoid  process.  It  sends  a  branch  to  the  muscle  and  leaves  its  posterior 
edge  about  its  middle.  It  then  passes  downward  and  outward  across  the  posterior 
cervical  triangle  under  the  deep  fascia  to  enter  the  deep  surface  of  the  trapezius.  If 
this  nerve  is  divided,  paralysis  of  the  trapezius  will  certainly  follow  and  as  it  is  a 
motor  nerve  the  shoulder  of  that  side  will  drop  considerably.  This  will  be  a  perma- 
nent deformity  because  motor  nerves  do  not  seem  to  have  their  functions  restored 
by  time  as  so  usually  occurs  when  the  nerves  of  sensation  are  divided. 

If  the  nodes  to  be  removed  are  superficial  ones  there  are  no  other  structures  to 
be  feared  and  the  operation  will  be  an  easy  one.  If  they  lie  deeper,  then  the  sheath 
of  the  sternomastoid  muscle  is  to  be  divided  and  the  muscle  pulled  outward.  Just 
above  the  level  of  the  cricoid  cartilage  a  small  artery,  the  sternomastoid  branch  of 
the  superior  thyroid,  enters  the  muscle  and  it  will  be  divided.  As  the  sternomastoid 
is  raised  and  pulled  outward  care  must  be  taken  to  avoid  wounding  the  spinal 
accessory  nerve.  As  this  nerve  enters  the  muscle  from  3  to  5  cm.  below  the  mastoid 
process  and  some  distance  back  from  the  edge  of  the  muscle,  if  it  is  necessary  to 
divide  the  muscle  it  is  best  done  high  up  above  the  entrance  of  the  nerve,  or  low 
down.  By  so  doing  the  nerve  supply  (from  the  spinal  accessory)  and  blood  supply 
are  not  interfered  with  and  the  function  of  the  muscle  is  not  so  much  impaired  as 
it  would  be  if  divided  near  the  middle.  The  nodes  not  only  possess  their  own 
capsule  but  also  a  covering  from  the  connective  tissue  in  which  they  lie.  There- 
fore to  remove  them  they  must  be  detached  and  separated  from  it  usually  by  blunt 
dissection.  When  these  strands  of  fibrous  tissue  from  the  nodes  to  the  surrounding 
parts  are  strong  they  have  to  be  caught  with  forceps  and  cut.  They  are  to  be 
clamped,  to.  avoid  possible  bleeding.  When  the  angle  of  the  jaw  is  reached  the 
communicating  branch  between  the  facial  and  external  jugular  veins  must  be 
clamped  and  cut.  The  parotid  gland  is  to  be  pulled  upward  and  inward.  The 
nodes  may  stick  to  the  jugular  vein  and  carotid  artery.  The  vein  is  on  the  outside 
and  is  likely  to  be  the  first  encountered.  When  distended  it  overlies  the  artery. 
If  collapsed  its  presence  may  not  be  suspected.  Feel  for  the  pulsation  of  the  carotid 
artery  and  avoid  the  structure  just  to  its  outer  side.  The  jugular  vein  may  be  so 
involved  in  the  mass  as  to  necessitate  its  removal.  In  such  a  case  remember  that 
posteriorly  between  it  and  the  carotid  artery  is  the  pneumogastric  nerve. 

The  sympathetic  nerve  hes  deeper  in  the  fascia  toward  its  posterior  surface  and 
is  not  so  likely  to  be  wounded.      Its  superior  cervical  ganglion  lies  opposite  the 


i6o  APPLIED    ANATOMY. 

second  and  third  vertebra;.  Working  still  higher,  the  transverse  process  of  the 
atlas  or  first  cervical  vertebra  will  be  felt  and  seen  below  and  to  the  inner  side  of  the 
mastoid  process.  The  connective  tissue  adherent  to  the  nodes  is  attached  to  this 
transverse  process  and  may  have  to  be  cut  loose  or  scraped  away.  In  doing  so 
keep  to  the  outer  edge  because  the  jugular  vein  and  internal  carotid  artery  lie  on  its 
anterior  surface. 

Beneath  the  sternomastoid  runs  the  anterior  scalene,  muscle  and  on  it,  coming 
from  the  third,  fourth,  and  fifth  cervical  nerves,  is  the  phrenic  nerve;  so  that  it  is 
not  permitted  to  dig  into  and  disturb  the  muscular  mass  to  the  outer  side  of  the 
common  carotid  artery  on  which  these  nodes  frequently  lie. 

In  operating  in  the  submental  region  there  is  nothing  to  fear.  The  space 
between  the  two  anterior  bellies  of  the  digastric  muscles  on  the  sides,  the  hyoid 
bone  below,  and  down  to  the  anterior  surface  of  the  mylohyoid  muscle  beneath,  can 
be  cleared  out  with  impunity. 

y^  ~      ■ 


Sternomastoid  muscL 
Anterior  scalene  muscL 


Internal  jugul; 

Omohyoid  muscl 


Occipitalis  major  nerve 
■Occipital  artery 
Occipitalis  minor  nerve 

Splenius  muscle 

Auricularis  magnus  nerve 

Superficial  cervical  nerve 

Levator  scapula?  muscle 

Spina]  accessory  nerve 

Trapezius 

Middle  scalene  muscle 


—  Posterior  scaleni 

—  External  jugula 


/n  t/ie  submaxillary  region  remember  that  the  fascia  covering  the  subma.xillary 
gland  is  thin,  so  that  the  gland  will  probably  be  exposed  as  soon  as  the  superficial 
structures  are  raised.  As  the  facial  artery  and  vein  cross  the  mandible  just  in  front 
of  the  masseter  muscle,  the  vein  is  posterior.  The  artery  goes  under  the  gland  and 
is  adherent  to  it,  so  that  as  the  gland  is  raised  the  artery  is  brought  up  also.  The 
facial  and  lingual  veins  usually  empty  into  the  internal  jugular,  but,  as  shown  in  Fig. 
1 68,  they  may  receive  a  communicating  branch  from  the  external  jugular  and  the 
anterior  jugular  and  continue  down  as  the  anterior  jugular  to  empty  into  the 
external  jugular  low  down  in  the  neck,  beneath  the  sternomastoid  muscle.  The 
hypoglossal  ner\'e  will  be  seen  lying  on  the  hyoglossus  muscle,  but  it  is  readily 
avoided.  The  lingual  artery  is  beneath  the  hyoglossus  muscle  anteriorly  but  both  it 
and  the  facial  must  be  looked  for  as  one  nears  the  posterior  belly  of  the  digastric. 

In  the  lower  cervical  region,  opposite  the  cricoid  cartilage,  the  omohyoid  muscle 
will  be  met.  It  will  sometimes  be  necessary  to  divide  it.  The  sternohyoid  and  sterno- 
thyroid muscles  and  the  thyroid  gland  are  to  be  drawn  inward  and  the  sternomastoid 
outward.      One  should  always  keep  away  from  the  thyroid  gland,   as  the  recurrent 


THE   NECK.  i6i 

laryngeal  nerve  runs  behind  it  and  on  the  oesophagus  near  the  trachea.  Cutting  it 
will  probably  cause  a  permanent  alteration  in  the  voice.  If  the  internal  jugular  vein 
has  been  removed,  as  it  may  be  on  one  side,  but  not  on  both,  beneath  it  one  is 
liable  to  encounter  the  inferior  thyroid  artery  below  Chassaignac's  tubercle  on  the 
si-xth  cervical  vertebra,  and  further  out  the  phrenic  nerve  on  the  scalenus  anticus  mus- 
cle, and  lower  down  the  transverse  cervical  and  suprascapular  arteries.  The  inferior 
thyroid  veins  usually  run  downward  to  empty  into  the  innominate  veins,  but  the 
lower  portion  of  the  anterior  jugular  vein  and  the  middle  thyroid  veins  will  probably 
have  to  be  ligated.  The  course  of  the  various  veins  is  quite  irregular  and  large 
venous  branches  may  be  encountered  at  any  place. 

In  the  posterior  cervical  triangle  the  spinal  accessory  nerve  must  be  avoided  as 
it  runs  down  and  back  from  the  middle  of  the  posterior  edge  of  the  sternomastoid 
muscle.  The  external  jugular,  posterior  jugular,  transverse  cervical,  and  supra- 
scapular veins  may  all  require  ligation.  Beneath  the  deep  fascia  (superficial  layer) 
are  the  descending  or  supraclavicular  branches  of  the  cervical  plexus  from  the  third 
and  fourth  cervical  nerves.  Care  should  be  taken  not  to  mistake  them  for  the 
spinal  accessory  nerve.  If  the  nerve  has  been  divided  it  should  be  sutured  together 
again  at  the  completion  of  the  operation.  It  is  hardly  necessary  to  caution  against 
wounding  the  subclavian  vein;  it  is  in  front  of  the  anterior  scalene  muscle.  The 
artery  is  behind  the  muscle.  Do  not  dig  under  it.  It  rests  on  the  pleura,  a  wound  or 
tear  of  which  may  mean  a  septic  pleurisy  and  death.  In  the  angle  formed  by  the 
junction  of  the  internal  jugular  vein  and  subclavian  on  the  left  side  is  the  thoracic 
duct.  If  wounded  death  may  ensue  through  persistent  leakage  of  lymph,  but  not 
infrequently  healing  eventually  occurs.  Wounding  of  the  corresponding  lymphatic 
duct  on  the  right  side  is  not  considered  so  serious,  the  chyle  being  carried  by  the  left 
duct.  The  cords  of  the  brachial  plexus  run  down  and  across  the  posterior  cervical 
triangle  above  the  subclavian  artery,  but  a  little  care  will  enable  one  to  avoid  them. 
This  is  one  of  the  regions  of  the  body  in  which  exact  surgery  is  essential. 

OPERATIONS  ON  THE  AIR-PASSAGES. 

The  pharynx  may  be  opened  just  below  the  hyoid  bone, — subhyoidean  phaj-yn- 
gotoiny.  The  larynx  may  be  opened  in  the  median  line, — tkyrotomy.  The  crico- 
thyroid membrane  may  be  opened, — laryngotomy.  The  trachea  may  be  opened, — 
tracheotomy . 

Subhyoidean  pharyngotomy  is  the  entering  of  the  pharynx  by  means  of  an 
incision  below  the  hyoid  bone.  This  is  an  extremely  rare  operation.  It  may  be 
performed  for  the  removal  of  foreign  bodies  or  tumors.  The  incision  may  be  made 
just  below  the  hyoid  bone  and  parallel  to  its  border.  This  will  divide  the  com- 
mencement of  the  anterior  jugular  vein,  perhaps  near  the  median  line,  perhaps  toward 
the  side.  A  transverse  vein  usually  runs  from  one  anterior  jugular  vein  to  the  other 
across  the  median  line  at  this  point.  Attached  to  the  hyoid  bone  nearest  to  the 
median  line  is  the  sternohyoid  muscle,  then  farther  out  the  omohyoid,  and  still  farther 
out  the  thyrohyoid.  A  small  artery,  the  thyrohyoid,  a  branch  of  the  superior  thyroid, 
or  sometimes  of  the  lingual,  will  be  divided. 

The  thyrohyoid  membrane  being  incised,  access  is  obtained  to  the  fatty  tissue 
at  the  base  of  the  epiglottis.  If  the  incision  is  carried  directly  backward  the  epiglottis 
will  be  cut  through  at  its  base.  If,  however,  it  is  kept  close  to  the  hyoid  bone  and 
made  upward,  the  pharynx  will  be  entered  in  front  of  the  epiglottis  and  at  the 
root  of  the  tongue.  If  the  incision  is  carried  too  far  toward  the  sides  the  superior 
thyroid  artery  and  even  the  external  carotid  itself  will  be  cut ;  if  carried  too  low  down 
on  the  thyrohyoid  membrane,  then  the  superior  laryngeal  artery  and  nerve  may  both 
be  wounded.      Attention  has  already  been  called  to  the  thyrohyoid  branch. 

Thyrotomy  is  the  division  of  the  thyroid  cartilage  in  the  median  line.  The 
sternohyoid  muscles  almost  touch  in  the  median  line.  The  division  should  be 
exactly  in  the  median  line.  This  will  avoid  wounding  the  anterior  jugular  veins.  If 
not  in  the  median  line  the  incision  will  wound  one  of  the  vocal  cords.  Impairment 
of  the  voice  certainly  follows  this  operation;  it  is  only  performed  for  the  removal  of 
foreign  bodies  or  growths. 


i62  APPLIED    ANATOMY. 

Laryngotomy  is  the  opening  of  the  cricothyroid  membrane.  It  is  rarely 
done,  but  it  is  of  ser\'ice  in  cases  of  choking  from  obstruction  of  the  larynx,  foreign 
bodies,  etc. 

There  is  not  sufficient  room  between  the  cricoid  and  thyroid  cartilages  to  do 
this  operation  properly  until  puberty  has  been  reached  and  the  larynx  has  enlarged. 
The  cricoid  cartilage  is  narrow  in  front  but  wide  behind.  Its  upper  edge  rises  rapidly 
as  it  passes  backward,  forming  an  upper  crescentic  border,  the  concavity  being 
upward.  The  lower  edge  of  the  thyroid  is  concave  downward.  Thus  the  two  edges 
make  an  oval  opening  in  front  which  in  children  is  too  small  to  hold  the  tracheotomy 
tube.  The  nearness  to  the  vocal  cords  is  also  a  serious  objection.  Performing  a 
laryngotomy  is  the  easiest  and  quickest  way  to  enter  the  air-passages.  Both  the 
thyroid  and  cricoid  cartilages  in  the  median  line  are  practically  subcutaneous.  A  lon- 
gitudinal incision  of  the  skin  is  usually  advised,  after  which  a  transverse  incision  is  em- 
ployed for  opening  the  cricothyroid  membrane.  The  tube  is  to  be  shorter  than  the  one 
ordinarily  used  for  tracheotomy.  The  cricothyroid  artery,  running  across  the  mem- 
brane, is  usually  too  insignificant  to  cause  any  trouble ;  it  is  nearer  the  thyroid  cartilage, 
therefore  the  cut  through  the  membrane  should  be  close  to  the  cricoid  cartilage. 

Tracheotomy  is  the  opening  of  the  trachea.  There  are  two  varieties,  the 
high  and  the  low,  according  as  the  tube  is  inserted  above  or  below  the  isthmus  of 
the  thyroid  gland.  When  in  the  adult  male  the  neck  is  in  line  with  the  axis  of  the 
body  the  lower  border  of  the  cricoid  cartilage  is  about  4  cm.  {i}4  in. )  above  the 
sternum.  When  the  head  is  tilted  far  back  the  larynx  is  drawn  upward  and  the 
lower  border  of  the  cricoid  is  6  cm.  (about  2i'2  in.)  above  the  sternum.  Hence  in 
doing  a  tracheotomy  the  head  is  to  be  tilted  far  back.  The  total  length  of  the 
trachea  is  10  to  12  cm.  (Morris,  Hensman),  beginning  opposite  the  sixth  cervical 
vertebra, — upper  border  in  the  child  and  lower  in  adults, — and  ending  opposite  the 
fifth  dorsal.  About  half  of  it  is  above  and  half  below  the  top  of  the  sternum.  It  is 
composed  of  14  to  20  rings.  In  the  adult  the  isthmus  of  the  thyroid  gland  covers 
the  second,  third,  and  fourth  rings.      There  are  about  eight  rings  above  the  sternum. 

According  to  Symington  and  Guersant  (Treves)  the  diameter  of  the  trachea  is 
about  as  follows: 

i^  to    2  years 5  mm. 

2      to    4  years 6  mm. 

4      to    S  years 8  mm. 

8      to  12  years 10  mm. 

12      to  15  years 12  mm. 

Adults 12-15  mm. 

A  knowledge  of  the  size  of  the  trachea  is  necessary  in  order  to  select  a  trache- 
otomy tube  of  a  size  suitable  to  the  particular  case.  The  liabilit}-  is  to  select  too 
large  a  tube  for  young  children,  particularly  infants.  If  this  is  done  it  may  be  very- 
difficult  to  introduce  the  tube,  or  the  trachea  may  even  be  torn  in  the  attempt.  In 
operating,  an  incision  2.5  to  3  cm.  long  is  to  be  made  in  the  median  line.  This 
may  cut  the  anterior  jugular  vein.  If  carried  near  to  the  sternum  it  will  certainly 
divide  the  communicating  branch  between  the  anterior  jugulars  at  that  point.  The 
top  of  the  incision  in  a  child  will  be  over  the  cricoid  cartilage,  and  as  soon  as  the  skin 
has  been  divided  the  finger  is  to  be  inserted  and  the  cricoid  cartilage  felt  and  recog- 
nized. This  will  show  how  deep  the  trachea  lies.  In  very  young  children  the 
isthmus  of  the  thyroid  gland  is  liable  to  come  up  to  the  cricoid  cartilage  and  the  dif- 
ficulty of  displacing  it  far  enough  down  to  allow  the  tube  to  be  inserted  is  such  that 
it  may  be  best  to  divide  it.  Therefore  after  the  skin  and  deep  fascia  have  been  divided 
and  the  cricoid  recognized  by  the  finger  the  soft  tissues  covering  the  trachea  imme- 
diately below  the  cricoid  are  grasped  on  each  side  with  a  haemostatic  forceps  and 
divided  between  them.  These  tissues  may  embrace  the  isthmus  of  the  thyroid  gland, 
the  edges  of  the  sternohyoid  muscles,  some  veins,  branches  from  the  superior  and 
inferior  thyroids,  and  the  fascia  covering  the  gland  and  overlying  the  trachea. 

The  trachea  should  be  cleared  before  opening  it.  A  sharp  hook  is  inserted  into 
the  cricoid  cartilage  to  steady  it  and  an  incision  is  made  into  the  trachea  from  below 
upward.     In  making  this  incision  the  utmost  care  must  be  taken  not  to  cut  through 


THE   NECK. 


163 


the  trachea  and  wound  the  oesophagus  behind.  The  trachea  of  a  child  is  not  the  hard 
resisting  structure  of  the  aduk.  It  is  a  soft  tender  tube  easily  compressed  and  readily- 
torn  by  roughness,  or  punctured  with  a  knife.  Forceps  do  not  readily  hold  in  it  and 
stitches  through  it  are  liable  to  tear  out.  Only  the  very  tip  of  the  point  of  the  knife 
should  be  allowed  to  enter  the  tube.  The  utmost  care  must  be  taken  to  keep  in  the 
median  line.  This  is  to  be  accomplished  by  using  the  cricoid  cartilage  as  a  guide 
and  by  seeing  that  the  position  of  the  head  is  straight.  Cutting  to  either  side  of  the 
trachea  wiU  cause  wounding  of  the  common  carotid  arteries.  Below  the  isthmus  of  the 
thyroid  gland  and  running  down  on  the  trachea  are  the  inferior  thyroid  veins.  The 
superior  and  middle  thyroid  veins  empty  into  the  internal  jugular  vein,  but  the 
inferior  thyroids  go  downward  to  empty  into  the  innominate.  These  veins  will  be  cut 
if  a  low  tracheotomy  is  done.  In  the  infant  the  innominate  artery  and  sometimes, 
though  rarely,  the  left  carotid  encroach  on  the  suprasternal  notch  and  may  be  wounded 
if   the  incision  is  carried  too  low.      The    left    innominate  vein  as  it  crosses   to   the 


Lingua]  and  facial  veins 


Internal  jugul; 


Sternohyoid  muscle 
Stemomastoid  muscle 
Sternothyroid  muscle 
Anterior  jugular  vein 
Inferior  thyroid  vein 


Hyoid  bone 
Thyroid  cartilage 
Cricothyroid  muscle 
Sternohyoid  muscle      ) 
Sternothyroid  muscle  [ 
Superior  thyroid  artery  j 
Cricoid  cartilage 
_-  Thyroid  gland 

Inferior  thyroid  artery 


Inferior  thyroid  vein 

Stemomastoid  muscle 

Trachea 

Communicating  branch  between  the 

anterior  jugular  veins 


Fig.  183. — Dissection  showing  the  parts  involved  in  operations  on  the  thyroid  gland  and  ; 

right  side  is  liable,  especially  in  very  young  children,  to  show  quite  plainly  above  the 
sternum  and  would  certainly  be  cut  if  the  deep  incision  was  carried  as  far  down  as 
the  top  of  the  sternum.  An  anomalous  artery,  the  thyroidea  ima,  a  branch  of  the 
innominate,  sometimes  passes  upward  on  the  trachea.  On  account  of  the  presence 
of  all  these  vessels  it  is  not  allowable  to  do  any  cutting  of  the  deep  parts  just  above 
the  sternum;  they  are  simply  to  be  depressed  by  blunt  dissection  and  kept  out  of 
the  way  with  retractors  while  the  trachea  is  being  incised.  The  cricoid  cartilao-e  is 
never  to  be  incised.  It  is  far  more  firm  and  resistant  than  the  trachea  and  it  serves 
to  keep  the  trachea  from  collapsing.  The  proximity  of  the  tracheotomy  tube  to  the 
vocal  cords  would  result  in  interference  with  their  function. 

The  method  of  Bose  consists  in  dividing  the  fascia  overlying  the  trachea  near 
the  cricoid  cartilage  and  pushing  it  down,  carrying  the  isthmus  and  veins  with  it, 
and  introducing  the  tube  into  the  space  so  cleared"  This  is  so  difficult  that  it  is 
better  to  divide  the  isthmus,   as  already  described. 


OPERATIONS  ON  THE  THYROID  GLAND. 

The  operations  which  are  done  on  the  thyroid  gland  are  ligation  of  its  arterial 
supply  and  complete  or  partial  removal.  These  necessitate  a  knowledge  particularly 
of  its  blood  supply  and  structure. 

The  thyroid  gland  consists  of  an  isthmus  and  two  lateral  lobes.      The  isthmus 


1 64 


APPLIED    AXATO-MY. 


crosses  the  second,  third,  and  fourth  tracheal  rings  in  the  adult.      In  children  it  may 
approach  nearer  to  the  cricoid  cartilage. 

The  lateral  lobes  lie  under  the  sternohyoid  and  the  sternothyroid  muscles. 
They  rise  as  high  as  the  oblique  line  on  the  sides  of  the  thyroid  cartilages  which 
marks  the  insertion  of  the  sternothyroid  muscles.  The  lobes  descend  to  the  leyel 
of  the  sixth  ring  of  the  trachea,  which  is  \.\\o  rings  below  the  isthmus,  about  two 
centimetres  aboye  the  sternum.  The  inferior  constrictor  of  the  phaiyn.x  is  beneath 
the  gland.  The  thyroid  gland  is  co\'ered  by  tk\&  pretracheal  fascia  and  possesses 
a  capsule  of  its  own  besides.  This  fascia  enyelops  the  gland  and  its  capsule,  and 
from   its  posterior  surface  is  prolonged   do^^■n   on  the  trachea   and   envelopes  the 


Omohyoid  muscle 

Sternothyroid  muscle 

Sternohyoid  muscle 


Sup.  thyToid 
artery  and  vein 


Sup.  parathjToid 


Inferior  thyroid  arter>- 

^Recurrent  larjmgeal  ner 
^Middle  thjT-oid  vein 
-  Inferior  th^Toid  i 

-Sternohyoid  muscle 
Fig.  1S4. — Excision  of  the  thyroid  gland. 


vessels  coming  to  and  lea\-ing  the  gland.  Therefore  we  might  say  that  the  inferior 
thyroid  \-eins  are  in  the  pretracheal  fascia. 

As  the  fascia  leaves  the  gland  at  the  sides  one  portion  of  it  blends  with  and 
helps  to  form  the  sheath  of  the  ^•essels.  The  other  or  deeper  portion  continues 
around  the  pharyn.x  and  oesophagus,  forming  the  buccopharyngeal  fascia.  In  freeing 
the  gland  and  its  capsule  from  the  o\'erlying  pretracheal  fascia  care  must  be  taken, 
as  pointed  out  by  James  Berry'  ("  Diseases  of  the  Thyroid  Gland,"  p.  269),  not  to 
be  led  by  this  fascia  too  far  posteriorly  and  therefore  wound,  as  has  been  done,  the 
pharyn.x  or  trachea. 

The  \'eins  of  the  gland  are  more  prominent  and  dangerous  than  the  arteries. 
They  ramify  beneath  the  capsule  and  as  long  as  the  capsule  is  not  torn  the  bleeding 
is  slight.  The  a7ieries  of  the  thyroid  gland  are  the  superior  and  inferior  thyroids 
■and  sometimes  the  thyroidea  ima.      The  superior  thyroid  comes   off  the  external 


THE   NECK.  i6s 

carotid  just  above  the  bifurcation.  It  rises  almost  to  the  greater  horn  of  the  hyoid 
bone  and  then  descends  to  the  thyroid  gland,  which  reaches  to  the  level  of  the  oblique 
line  on  the  thyroid  cartilage;  it  supplies  the  upper  portion  of  the  gland,  particularly 
the  anterior  portion,  but  also  sends  a  branch  down  the  posterior  surface.  The 
vessels  crossing  the  median  line,  contrary  to  what  is  often  the  case  in  the  arteries  of 
the  lip  and  even  the  scalp,  are  very  small.  The  superior  thyroid  is  superficial  and 
presents  no  special  difficulty  in  ligation.  The  vein  runs  beneath  it  on  its  course  to 
the  internal  jugular.  The  infei'ior  thyroid  artery,  a  branch  of  the  thyroid  axis, 
crosses  behind  the'  common  carotid  artery  about  the  level  of  the  seventh  cervical 
vertebra,  about  on  a  line  with  the  lower  edge  of  the  isthmus.  It  enters  the  gland 
from  the  side  and  not  from  below  and  ramifies  on  its  posterior  surface  often  as  a 
single  large  trunk  beneath  the  capsule  giving  ofl[  branches  to  the  parenchyma. 
Usually  it  is  in  front  of  the  recurrent  laryngeal  nerve,  but  the  middle  cervical  gan- 
glion of  the  sympathetic  lies  on  it.  Sometimes  the  artery  breaks  into  branches  before 
it  enters  the  gland.  In  such  cases  the  recurrent  laryngeal  nerve  may  run  between 
these  branches  and  so  be  injured  in  removing  the  gland. 

The  thyroidea  iiiia  artery  when  present  enters  the  gland  from  below,  coming  up 
on  the  trachea  usually  from  the  innominate,  in  which  case  the  innominate  is  apt  to 
come  off  more  to  the  left  side  and  so  bring  the  common  carotid  closer  to  the  trachea 
than  usual.      It  may  also  spring  from  the  aorta  or  from  the  right  carotid  artery. 

The  Veins. — There  are  three  sets  of  veins,  a  superior,  a  middle,  and  an  inferior 
thyroid,  and,  as  Kocher  has  pointed  out,  an  accessory  thyroid  between  the  middle 
and  inferior  ones.  The  veins  ramify  under  the  capsule  and  form  a  plexus,  which 
in  goitre  is  much  enlarged  and  communicates  freely  across  the  median  line  at  the 
upper  and  lower  portions  of  the  isthmus.  The  superior  and  middle  thyroids  pass 
outward  to  empty  into  the  internal  jugular.  Still  lower  is  the  accessory  inferior  thy- 
roid, which  may  empty  into  the  internal  jugular,  as  do  the  two  above  it,  or  it  may  pass 
down,  as  does  the  inferior  thyroid  vein,  and  empty  into  the  innominate.  The  inferior 
thyi'oid  vein  does  not  follow  the  artery  of  the  same  name  but  with  its  fellow  of  the 
opposite  side  passes  directly  downward  in  front  of  the  trachea  to  empty  into  the 
innominate  vein.  Its  importance  in  operations  on  the  trachea  has  already  been  alluded 
to  in  speaking  of  tracheotomy. 

In  removing  the  gland  the  superior  thyroid  artery  is  found  at  the  upper  outer 
angle,  the  ligature  should  be  placed  sufficiently  far  out  to  include  the  branch  to  the 
posterior  surface  of  the  gland.  In  ligating  the  inferior  thyroid  arteries  they  are  to 
be  sought  at  the  lower  portion  of  the  sides  of  the  gland  and  are  to  be  ligated  either 
close  to  the  gland  or  isolated  by  pulling  the  carotid  artery  outward,  and  tied  as  they 
make  the  bend  at  the  edge  of  the  anterior  scalene  muscle.  Between  these  two 
points  lies  the  recurrent  laryngeal  nerve,  usually  behind  the  artery.  Halsted  advises 
that  each  separate  branch  be  ligated  as  it  enters  the  gland  to  avoid  those  supplying 
the  parathyroids.  The  gland  is  covered  by  the  omohyoid,  sternohyoid,  and  sterno- 
thyroid muscles.  If  these  cannot  be  drawn  aside  they  should  be  divided  near  their 
upper  ends  in  the  same  manner  as  already  advised  in  the  case  of  division  of  the 
sternomastoid  in  removing  tuberculous  nodes.  The  sternomastoid  muscle  will  have 
to  be  drawn  outward. 

The  internal  jugular  vein  often  overlaps  the  common  carotid  artery,  reaching 
sometimes  even  to  its  inner  side,  so  that  the  position  of  the  artery  is  not  a  sure  guide 
to  the  location  of  this  vein. 

When  a  goitre  dips  behind  the  sternum  the  presence  of  the  left  innominate 
vein  should  not  be  forgotten. 

THE  PARATHYROID  BODIES. 

The  parathyroid  bodies  are  usually  four  in  number,  but  rarely  there  may  be  five 
or  six.  They  are  6  to  7  mm.  long,  3  to  4  mm.  broad,  and  1.5  to  2  mm.  thick.  The 
most  constant  site  of  the  superior  parathyroid  is  at  the  middle  or  junction  of  the  upper 
and  middle  thirds  of  the  posterior  edge  of  the  thyroid  gland  opposite  the  cricoid  carti- 
lage. The  lower  parathyroid  is  near  the  lower  pole,  but  may  be  below  it.  They  are 
small  brownish  bodies  in  the  meshes  of  the  loose  connecti\-e  tissue  forming  the  outer 
capsule  of  the  gland.      Often  they  are  quite  distinct  from  the  gland,  but  sometimes 


i66 


APPLIED    ANATOMY. 


they  lie  in  a  cleft  in  the  gland  and  thereby  escape  recognition.  They  possess  a  separate 
capsule.  They  are  supplied  by  a  separate  artery,  the  parathyroid,  a  branch  of  the 
inferior  thyroid.  This  latter  usually  gives  oE  two  parathyroid  arteries,  one  to  each 
body.  Ginsburg  (yUniv.  Penna.  Med.  Bulletin,  Jan.,  1908)  has  demonstrated  a  free 
anastomosis  with  the  vessels  of  the  opposite  side.  In  many  cases  it  is  practically 
impossible  to  avoid  wounding  or  removing  the  parathyroids  in  operations — Halsted 
has  suggested  three  means  of  avoiding  their  removal,  viz. :  ( i)  slice  off  and  leave  the 
piece  of  thyroid  gland  supposed  to  contain  the  parathyroids;  (2)  ligate  the  superior 


=  Inferior  constrictor 
Superior  thyroid  artery 

Cricoth>Toid  muscle 
Superior  parathyroid 
■Inferior  thyroid  artery 

Thyroid  gland 

Inferior  parathjToid 

CEsophagus 

Recurrent  laryngeal  nerve 


Fig.  185. — Showing  the  parathyroid  bodies. 

and  inferior  thyroids,  and  a  week  or  two  later  perform  a  subcapsular  enucleation  of  the 
thyroid;  (3)  search  for  each  parathyroid  by  following  out  the  ramifications  of  the 
inferior  thyroid  artery — this  is  the  best  method  of  finding  them  in  post-mortem 
examinations. 

CESOPHAGUS— CERVICAL  PORTION. 

The  oesophagus  runs  from  the  level  of  the  cricoid  cartilage  to  the  stomach. 
The  cricoid  is  opposite  the  sixth  cervical  vertebra  and  the  cardiac  or  oesophageal  end 
of  the  stomach  is  opposite  the  lower  border  of  the  tenth  thoracic  vertebra.  It  is  in  the 
median  line  above,  then  curves  slightly  to  the  left  until  the  root  of  the  neck  is 
reached,  when  it  returns  to  the  median  line  opposite  the  fifth  thoracic  vertebra. 

It  is  in  front  of  the  spine  and  the  prevertebral  fascia.  The  layer  of  fascia  between 
its  anterior  surface  and  the  trachea  is  extremely  thin.  On  each  side  are  the  common 
carotid  arteries  and  the  sheath  of  the  vessels.  The  right  recurrent  laryngeal  nerve 
winds  around  the  commencement  of  the  first  portion  of  the  subclavian,  and  passes 


THE   NECK 


167 


inward  and  upward  behind  the  common  carotid  artery  to  reach  the  groove  between 
the  trachea  and  oesophagus  in  which  it  ascends  to  the  larynx. 

On  the  left  side  the  recurrent  laryngeal  nerve  winds  around  the  arch  of  the  aorta 
and  ascends  in  the  groove  on  the  left  side  between  the  trachea  and  oesophagus.  The 
left  carotid  artery  is  closer  to  the  oesophagus  than  the  right.  The  narrowest  point  of 
the  lumen  is  at  the  cricoid  cartilage.  Its  next  narrow  point  is  where  it  crosses  the  aorta 
and  left  bronchus.  This  is  opposite  the  upper  part  of  the  second  piece  of  the  sternum 
or  the  upper  border  of  the  fifth  thoracic  vertebra.  The  third  narrow  portion  is  the 
cardiac  opening  into  the  stomach.  Mouton  (Tillaux,  "Anat.  Topograph./'  p.  418) 
gives  the  diameter  of  the  oesophagus  at  each  of  these  three  points  as  14  mm. 

Foreign  Bodies. — Foreign  bodies  if  they  pass  the  cricoid  cartilage  are  most 
liable  to  stop  at  the  aorta  and  the  left  bronchus.      This  is  opposite  the  angle  of  Ludwig 


Left  common 
carotid  artery 

Vagus  nerve- 
Internal  jugular 

Inferior  thyroid 
artery 

Vertebral  artery 

Thoracic  duct 

Phrenic  nerve 
Recurrent  laryn- 
geal nerve 
Subclavian 
artery 
Bronchial  artery 

Pulmonary  artery 

Left  vagus  nerve-j — ;- 


Internal  jugular 

-Vagus  nerve 
Common  carotid 

Inf. thyroid  artery 

Vertebral  artery 
Trachea 
Recurrent  laryn- 

CEsophagus 

Vagus  nerve 

Phrenic  nerve 

Vena  azygos 

major 

Right  bronchus 

Right  pulmonary 
artery 

Pulmonary  vein 


Fig.  186. — Relations  of  the 


deal  portion  of  the  cesophagus,  viewed  posteriorly. 


and  the  second  rib,  so  that  the  foreign  body  is  either  at  the  root  of  the  neck  or  just 
below  the  top  of  the  sternum.  If  it  passes  the  two  upper  constrictions  it  will  prob- 
ably pass  the  third,  because  the  cardiac  constriction  is  caused  by  the  diaphragm,  which 
relaxes  and  allows  the  body  to  enter  the  stomach. 

CEsophagotomy, — In  operating,  an  incision  is  made  along  the  anterior  border 
of  the  left  sternomastoid  muscle  from  the  sternoclavicular  joint  upward.  The  anterior 
jugular  vein  will  be  cut.  After  opening  the  deep  fascia  the  sternomastoid  is  to  be 
pulled  outward.  The  omohyoid  is  to  be  drawn  up  and  out  and  also  the  lower  por- 
tion of  the  sternohyoid  and  perhaps  the  sternothyroid. 

The  middle  thyroid  and  perhaps  an  accessory  thyroid  vein  are  divided  and  the 
thyroid  gland  and  trachea  drawn  inward.  The  trachea  is  to  be  identified  by  the 
sense  of  touch.  The  inferior  thyroid  artery  is  behind  the  sheath  of  the  vessels  and  is 
so  high  that  it  is  not  likely  to  be  injured.  The  recurrent  laryngeal  nerve  must  be 
looked  for  between  the  cesophagus  and  trachea,  and  avoided.  In  going  deep  down 
care  must  be  taken  not  to  injure  the  innominate  vein,  w^hich  comes  well  up  towards  the 
top  of  the  sternum. 


i68 


APPLIED    ANATOMY. 


CUT  THROAT. 

The  most  frequent  site  of  the  incision  in  cases  of  cut  throat  is  between  the  hyoid 
bone  and  thyroid  cartilage.  If  above  the  hyoid  bone,  the  incision  will  divide  the 
mylohyoid,  geniohyoid,  geniohyoglossus,  and  hyoglossus  muscles,  and  perhaps  the 
dio-astric  and  stylohyoid.  If  it  goes  far  back  it  may  wound  the  submaxillary  gland 
or  duct,  the  facial  or  lingual  arteries  and  veins,  and  the  hypoglossal  nerve.  The 
commencement  of  the  anterior  jugular  will  certainly  be  divided  and  the  external 
iuo-ular  may  also  be  wounded.  The  cut  passes  through  the  base  of  the  tongue  and  the 
upper  portion  of  the  epiglottis.  The  tip  of  the  epiglottis  is  sometimes  entirely  cut  off. 
If  in  the  thyrohyoid  space,  the  incision  passes  a  short  distance  above  the  vocal  cords. 
The  sternohyoid,  omohyoid,  and  thyrohyoid  muscles  are  divided.  If  prolonged 
backward  the  pharyn.x  will  be  opened  and  perhaps  the  arytenoid  cartilages  wounded. 
The  superior  thyroid  artery  is  likely  to  be  cut.  This  is  the  vessel  most  often  divided 
in  suicidal  wounds.  The  carotid  arteries  and  internal  jugular  veins  are  deep  and  far 
back,  lying  under  the  edge  of  the  sternomastoid  muscle,  and  are  rarely  wounded. 


Sternohyoid  muscli 


Sternothyroid  muscle 


Inferior  thyroid  artery 
Common  carotid  artery' 


Sternomastoid  muscle 


Recurrent  lar\m- 


Fig.  1S7. — Exposing  the  cesophagus. 

If  these  are  cut,  death  usually  rapidly  ensues  from  hemorrhage.  The  superior 
laryngeal  nerve  may  be  injured  as  it  pierces  the  thyrohyoid  membrane.  This  nerve 
is  sensory  and  its  division  is  followed  by  anaesthesia  of  that  half  of  the  laryn.x  to 
which  it  is  distributed.  This  favors  the  entrance  of  food  and  liquids  into  the  larynx 
and  so  may  cause  a  fatal  septic  pneumonia.  If  thfough  the  thyroid  cai'tilage  the 
incision  may  wound  the  vocal  cords.  They  lie  just  beneath  the  most  prominent 
part  of  the  thyroid  cartilage  and  just  below  its  median  notch.  If  through  the  trachea, 
the  incision  may  wound  the  thyroid  gland,  which  reaches  from  about  the  sixth  ring 
of  the  trachea  to  the  oblique  line  on  the  thyroid  cartilage. 

^Bleeding  from  the  wounded  thyroid,  if  the  gland  is  normal  in  size,  is  not  likely 
to  be  excessive.  Below  the  cricoid  cartilage  the  cesophagus  may  be  wounded,  above 
it  the  pharyn.x  may  be  opened.  The  two  large  sternomastoid  muscles  being  put  on 
the  stretch  tend  to  protect  the  large  vessels  beneath.  Suppuration  not  infrequently 
accompanies  these  wounds  of  the  neck  in  which  the  air  and  food  passages  are  in- 
volved and  may  give  rise  to  collections  of  pus  which  may  travel  between  the  fascias,  as 
previously  described.  In  treatment  it  is  customary  to  cleanse  the  wounds  and  approxi- 
mate the  various  injured  tissues  as  carefully  as  possible,  and  feed  by  a  stomach  tube. 


THE   NECK. 


169 


AFFECTIONS  OF  THE  NECK. 

Cervical  Cysts  and  Fistulae. — The  neck  is  the  seat  of  some  very  peculiar 
cystic  tumors  and  fistulae  which  are  connected  with  developmental  defects.      They 


Second  cleft 
Third  arch 
Third  cleft 
Fourth  arch 


Fig.  188. — Fcetus,  2Sth  day  (after  His).     Showing  branchial  (visceral)  arches  and  clefts  or  furrows. 


are  either  lateral  or  median  in  location.  The  lateral  originate  from  the  visceral 
(branchial)  clefts,  while  the  median  are  connected  with  the  thyroglossal  duct.  The 
visceral  clefts  are  depressions  between  the  visceral  arches.  These  arches,  five  in 
number,  spring  forward  from  each  side  of  the  embryo  to  form  the  neck  region. 
Sometimes  these  arches  are  called  branchial  arches  from  the  fact  of  their  going  to 
form  the  branchiae  or  gills  of  fishes  and 
some  of  the  other  lower  orders  of  animals. 

The  first  visceral  arch  divides  into 
two  parts,  a  maxillary  part  forming  the 
upper  jaw  and  a  mandibular  part  form- 
ing the  lower  jaw.  Defects  in  the  max- 
illary arch  producing  harelip  and  cleft 
palate  have  already  been  described. 
Two  of  the  ear  bones,  the  incus  and 
malleus,  are  also  formed  by  the  mandib- 
ular portion  of  the  first  visceral  arch. 

The  second  visceral  arch  forms  the 
stapes,  the  styloid  process,  the  stylo- 
hyoid ligament,  and  the  lesser  horn  of 
the  hyoid  bone. 

The  thii-d  visceral  arch  becomes  the 
body  and  greater  horn  of  the  hyoid  bone. 

The  fourth  a.nd  fifth  visceral  arches 
blend  and  form  the  soft  structures  of  the 
side  of  the  neck. 

The  first  visceral  cleft,  called  the 
hyomandibular  cleft  from  its  being  be- 
tween the  hyoid  bone  and  the  mandible, 
forms  the   middle   ear   and  Eustachian 

tubes  from  its  inner  portion  and  the  external  auditory  meatus  from  its  outer  portion. 
The  membrana  tympani  is  the  remains  of  the  membrane  which  stretched  across  from 
one  arch  to  the  other.  Cervical  fistulae  are  formed  by  the  persistence  of  a  \-isceral 
cleft.      As  the  first  visceral  cleft  persists  normally  in  the  structures  already  named,  it 


Fig.  1S9. — Points  of  opening  of  sinuses  originating 
from  the  thvroglossal  duct  and  branchial  clefts.  (Modi- 
fied from  Sutton.) 


lyo 


APPLIED    ANATOMY. 


in  itself  does  not  form  pathological  fistulse,  but  congenital  fistulae  are  sometimes 
encountered  in  the  external  ear  which  are  the  remains  of  the  clefts  between  the 
tubercles  of  which  the  ear  is  formed. 

Cervical  fistulae  or  sinuses  may  extend  either  completely  through,  from  the 
surface  to  the  pharynx,  or  may  open  internally  or  externally,  or  be  closed  at  both 
ends,  in  which  last  case  the  contents  accumulate  and  form  a  cervical  cyst. 

FistulcB  arising  from  the  second  visceral  cleft  open  externally  opposite  the  thyro- 
hyoid space  in  front  of  the  sternomastoid  muscle.  Internally  they  open  into  the 
recess  holding  the  tonsil. 

FistulcE  arising  from  the  third  and  fourth  visceral  clefts  open  externally  lower 
down  nearer  the  sternoclavicular  articulation  in  front  of  the  sternomastoid  muscle  and 

internally  in  the  sinus  pyriformis.  The 
persistence  of  the  third  and  fourth 
visceral  clefts  internally  may  produce 
pharyngeal  diverticula,  as  already 
noted  in  discussing  that  region. 

In  attempting   the  cure  of  cysts 
and  fistulse  due  to  persistence  of  the 


Thyroglossal  duct 


Fig.  190. — Median  cervical  pouch  or  cyst  arising  from  the 
thyroglossal  duct. — Marshall's  case. 

visceral  clefts  it  is  evident  that  as  they  are  lined  with  a  secreting  epithelium  this  must 
be  destroyed  or  removed,  or  a  recurrence  will  take  place.  In  attempting  to  dissect 
them  out  one  must  be  prepared  to  follow  them  through  the  structures  of  the  neck 
to  the  pharynx  inside.    It  is  needless  to  say  this  may  be  a  serious  procedure. 

Hueter  (quoted  by  Sutton)  followed  one  between  the  two  carotid  arteries  into  the 
pharynx.     These  cysts  and  listulse  may  be  noted  at  birth  or  may  develop  later  in  life. 

Hydrocele  of  the  Neck. — There  are  other  cystic  tumors  of  the  neck  which 
are  congenital,  being  noticed  at  birth,  and  which  grow  to  a  large  size.  They  are 
often  wide-spread,  extending  not  only  between  the  tissues  of  the  neck  below  the 
deep  fascia  but  even  into  the  axilla.  Their  walls  are  thin,  coiisisting  sometimes  only 
of  a  layer  of  lining  epithelium  and  the  surrounding  tissues.  On  this  account  it  is 
impossible  to  dissect  them  out.  The  use  of  injections  and  setons  has  been  aban- 
doned as  too  dangerous.  They  rarely  require  treatment,  as  they  tend  to  disappear 
spontaneously.  Mr.  J.  Bland  Sutton  ascribes  their  origin  fij'st  to  congenitally  dilated 
lymph-spaces;  second  a.?,  resembling  the  cervical  air-sacs  that  exist  in  the  howling 
monkeys;  and  third  that  possibly  some  of  them  may  be  related  to  a  persistence  of 
some  portion  of  a  branchial  cleft. 

Median  cervical  fistulae  and  cysts  originate  in  connection  with  the  thyro- 
glossal duct.     This,  in  the  embryo,  leads  from  the  foramen  caecum  at  the  root  of  the 


THE    THORAX.  171 

tongue  through  to  the  posterior  surface  of  the  hyoid  bone  and  thence  downward  and 
forward  to  the  isthmus  of  the  thyroid  gland.  It  begins  to  atrophy  in  the  fifth  week 
and  is  obliterated  by  the  eighth.  According  to  Sutton  these  cysts  are  never  congen- 
ital but  occur  soon  after  birth  or  as  late  as  the  fourteenth  year.  They  appear  as 
rounded,  cystic  tumors  just  below  the  hyoid  bone  or  over  the  thyroid  cartilage.  They 
either  inffame  and  break  of  their  own  accord,  discharging  externally,  or  are  opened  by 
the  surgeon  and,  contrary  to  what  is  the  case  in  hydroceles  of  the  neck,  ne\'er  tend  to 
disappear,  but  a  sinus  remains.  At  times  it  almost  heals,  then  the  contents  accumulate 
and  a  cyst  forms,  this  again  breaks  and  a  sinus  results  as  before.  In  attempting  a  cure 
by  operation  the  sinus  should  be  followed  up  behind  the  hyoid  bone.  In  one  case  after 
two  failures  of  attempted  e.xcision  a  cure  was  obtained  by  destroying  the  tract  by 
introducing  a  small  galvanocautery  point.  Unless  every  portion  of  the  lining  mem- 
brane be  completely  destroyed  the  cells  will  go  on  secreting  and  reproduce,  in  a 
short  time,  the  original  condition.  Failure  to  cure  these  sinuses  and  cysts  by  excision 
often  occurs,  notwithstanding  the  exercise  of  the  greatest  care. 

The  lower  portion  of  the  thyroglossal  duct  may  persist  in  the  form  of  the  pyramid 
or  third  lobe  of  the  thyroid  gland,  which  arises  from  the  isthmus  or  from  the  left  side 
and  ascends  as  far  as  the  hyoid  bone,  to  which  it  is  attached. 

THE  THORAX. 

The  thorax  or  chest  is  that  portion  of  the  trunk  which  lies  between  the  neck 
and  the  abdomen.  It  is  composed  of  a  bony  framework  reinforced  by  soft  parts, 
and  contains  the  main  organs  of  circulation  and  respiration.  The  oesophagus,  an 
organ  of  the  digestive  tract,  simply  passes  through  it  to  the  regions  below.  The 
chest-walls  as  well  as  the  parts  contained  within  them  are  affected  by  wounds  and 
disease,  especially  the  heart  and  its  associated  great  vessels,  and  the  lungs  and 
pleurae.  These  organs  are  essential  to  life,  like  the  brain  and  spinal  cord,  and  like 
them,  are  encased  in  a  bony  framework.  It  is  an  example  of  bones  performing  a 
protecting  function  in  addition  to  a  supporting  one. 

The  functions  of  the  heart  and  lungs  are  influenced  by  constitutional  diseases  in 
addition  to  their  own  local  affections,  hence  they  serve  as  guides  to  the  general  bodily 
condition,  and  the  condition  of  the  respiration  and  circulation  is  continually  being  exam- 
ined for  the  purposes  of  diagnosis,  prognosis,  and  treatment,  even  when  the  heart  and 
lungs  themselves  are  not  involved.  To  make  these  examinations  intelligently,  neces- 
sitates a  knowledge  of  the  organs  themselves  and  their  relation  to  one  another  and  the 
surrounding  parts.    This  is  essential  for  the  physician  even  more  than  the  surgeon. 

The  chest-walls  are  composed  of  a  bony  framework  joined  and  bound  together 
and  covered  by  soft  parts. 

The  bones  of  the  chest  consist  of  the  sternum,  ribs,  and  thoracic  vertebra.  The 
clavicle  and  scapula  compose  the  shoulder-girdle  and  belong  to  the  upper  extremity. 
The  human  skeleton  is  divided  into  an  axial  portion  and  an  appendicular  portion.  The 
axial  portion  embraces  the  skull,  the  vertebral  column,  including  the  sacrum  and 
coccyx,  the  hyoid  bone,  the  sternum,  and  the  ribs.  The  appendicular  portion  con- 
sists of  the  shoulder-girdles  and  upper  extremities  and  the  pelvic  girdles  and  lower 
extremities. 

The  bony  chest  is  subject  to  disease  and  injury  as  well  as  to  defects  in  develop- 
ment, and  to  deformities  due  to  these  causes. 

Shape  of  the  Chest. — The  chest  is  conical  in  shape,  being  small  above  and 
large  below.  In  transverse  section  it  is  kidney-shaped,  the  hilus  of  the  kidney  being 
represented  by  the  vertebrje.  In  the  foetus  the  anteroposterior  diameter  is  greater 
than  the  transverse,  thus  resembling  the  thorax  in  the  lower  animals.  After  birth 
and  in  infancy  the  two  diameters  are  nearly  equal,  hence  we  have  the  rounded  chest 
of  the  child.  As  growth  and  development  progress  the  transverse  diameter  increases 
more  than  the  anteroposterior,  so  that  at  about  the  second  year  the  chest  has  become 
oval  and  in  adults  the  transverse  diameter  is  one-fourth  greater  than  is  the  antero- 
posterior. 

Variations  in  the  shape  of  the  chest  are  mainly  the  result  of  disease.  In  child- 
hood, rachitic  disease  (rickets)  produces  a  lateral  flattening  and  a  projection  of  the 


APPLIED    AXATOMY. 


sternum.  If  the  sternum  projects  markedly  it  constitutes  what  is  known  as  pigeon 
breast,  the  chest  in  such  a  condition  being  longer  from  before  backward  than  from  side 
to  side.      In  this  disease  also  there  may  be  a  depression  on  each  side  of  the  sternum, 


Clavicular  articulation 
Manubrium 


Xiphostemal  articulation 


Fig.  192. — The  bony  thorax. 

the  back  is  rounded  owing  to  the  bending  of  the  vertebral  column,  and  the  points  of 
junction  of  the  ribs  and  cartilages  are  enlarged,  this  latter  constituting  what  is  known 

as  beading  of  the  ribs.      These  beads  are 
felt  as  rounded  enlargements  at  the  sternal 
"*"  e.\tremities   of    the   ribs   and  form    a    line 

parallel  to  the  sternum  above  and  sloping 
outward  below.  This  line  of  beads  has 
been  called  the  ' '  rachitic  rosary. ' '  From 
the  level  of  the  ensiform  cartilage  a  groove 
passes  out  toward  the  sides ;  this  has 
been  called  "'  Harrison' s  groove^'  (see 
Fig.  193).  Sometimes  the  lower  end  of 
the  sternum  is  pressed  inward,  forming  a 
deep  funnel-shaped  depression  constituting 
the  deformity  known  as  '\fun71el  chest" 
or  the  ^ ^  Trichterbmst"  of  the  Germans. 
This  condition  of  the  chest,  with  the 
exception  of  the  beading,  is  also  produced 
in  children  by  obstruction  to  the  breathing 
from  enlargement  of  the  tonsils,  from  the 
presence  of  adenoid  growths  in  the  pharynx, 
and  from  hypertrophy  of  the  turbinate 
bones,  all  of  which  interfere  particularly 
with  nasal  respiration. 

Diseases  of  the  lungs  and  pleurse  alter 
the  shape  of  the  chest.  In  emphysema  and 
when  distended  by  plural  eflusions,  the 
thorax  becomes  more  rounded  in  shape, 
forming  what  is  called  the  "  barrel-shaped 
chest."  In  phthisis  the  wasting  of  the  tissues  and  contraction  of  the  lungs  causes  the 
chest  to  collapse.      The  ribs  slope  more  sharply  do\\nward  and  the  chest  becomes 


193- — Child  showing  H; 

the  ensiform  cartilage 


groove  opposite 


THE    THORAX. 


173 


longer  and  flatter,  the  anteroposterior  diameter  being  diminished.  The  angle  made 
by  the  lower  ribs  as  they  ascend  ■  to  the  sternum  is  called  the  costal  angle ;  this 
becomes  decreased  in  phthisis.     This  form  of  chest  is  known  as  the  '"phthisical  chests 


-Barrel  chest  of  ( 


195. — Flat  chest  of  phthi; 


When  the  flatness  is  marked  it  is  sometimes  called  the  '  'flat  chest. ' '  When  the  scapulas 
project  like  wings  it  is  called  "alar"  or  " pterygoid  chest." 

In  Pott' s  disease,  or  caries  of  the  spine,  as  the  kyphosis  develops  the  chest  falls  for- 


FiG.  ig6. — Kyphosis  from  Pott's  disease,  or  caries 
of  the  lower  thoracic  vertebra;.  The  curvature  is  an 
angular  anteroposterior  one. 


Fig.  197. — Scoliosis,  or  lateral  curvature  of  the  spii 


ward  and  its  anteroposterior  diameter  is  increased.  The  abdominal  contents  are  crowded 
up  into  the  chest  and  push  the  sternum  and  lower  ribs  forward.  Associated  with  this 
deformity  is  oftentimes  a  lateral  deviation  of  the  parts  above  the  site  of  the  disease. 


174  APPLIED    ANATOMY. 

In  scoliosis,  or  lateral  curvature  of  the  spine,  the  distortion  is  uneven,  being  a 
compression  of  the  thorax  from  above  downward  and  a  twisting  around  a  vertical 
axis.  The  deformit}'  is  frequently  so  se\'ere  as  to  cause  the  lower  ribs  to  rest  on  the 
iliac  crests.  It  is  in  order  to  detect  these  diseases  in  their  early  stages  that  a  know- 
ledge of  the  shape  of  the  normal  chest  is  so  essential. 

THE   STERNOl. 

The  sternum  consists  of  three  pieces:  the  manubrium  ox  presternum,  gladiolus 
or  mesosternum-,  and  xiphoid  cartilage  or  metasternum.  It  is  developed  in  two 
lateral  halves.  Should  these  fail  to  unite  an  opening  is  left  in  the  bone  through  which 
the  pulsations  of  the  heart  have  been  seen  and  felt.  The  junction  of  the  first  and 
second  pieces  of  the  sternum  is  opposite  the  second  rib.  The  seventh  is  the  last  rib 
to  articulate  with  the  sternum  directly. 

The  first  and  second  pieces  of  the  sternum  are  connected  by  a  joint  which  per- 
sists to  ad\'anced  age.  The  projection  caused  bA'this  joint  is  called  the  angulus  sterni 
or  angle  of  LudcC'ig.  Fractures  pass  either  through  this  joint,  opposite  the  second 
rib,  or  through  the  bone  just  below  it.  They  are  produced  by  both  direct  and 
indirect  force.  Usually  the  upper  fragment  is  beneath  the  lower  one.  It  is  however 
more  true  to  state  that  the  lower  fragment  is  displaced  anteriorly.  Any  marked  pos- 
terior displacement  of  the  upper  fragment  would  tend  to  press  on  the  trachea  and  in- 
terfere with  breathing;  the  trachea  bifurcates  opposite  the  joint.  As  the  pleurae  and 
lungs  of  the  two  sides  almost  or  quite  touch  behind  the  second  piece  of  the  sternum, 
they  ma^' be  wounded  and  emphysema  may  occur.  The  heart  also  maybe  wounded. 
Suppuration  has  followed  these  injuries,  in  which  case  it  will  be  necessarj'  to  trephine 
the  sternum  to  give  exit  to  the  pus.  The  necessity  of  avoiding  wounding  of  the 
pleurae  in  such  a  procedure  is  e\'ident,  as  it  would  be  follo^'ed  by  collapse  of  the  lung 
and  empyema. 

THE    RIBS   AND    COSTAL    CARTILAGES. 

The  ribs  are  frequently  fractured,  sometimes  they  become  affected  with  caries, 
and  in  operating  the  chest  is  frequently  opened  between  them  or  portions  of  them 
are  excised.  They  are  both  elastic  and  movable,  and  difficult  to  break;  hence  frac- 
ture is  almost  always  due  to  direct  violence,  and  this  \-iolence  may  be  so  great  as 
sometimes  to  cause  death.  Normally  there  are  twelve  ribs  on  each  side,  but  some- 
times there  is  an  e.xtra  cervical  or  lumbar  rib.  These  are  both  rare,  the  latter  the 
more  so. 

The  se\'en  upper  ribs  are  called  tj-tce  ribs  because  they  articulate  with  the  sternum. 
The  remaining  f^^'e  are  ca\\&A  false  ribs,  the  ele\-enth  and  twelfth  being  Jloating  ribs. 
The  eighth,  ninth,  and  tenth  ribs  each  articulate  by  their  cartilages  with  the  rib  above. 
The  tenth  forms  the  lower  margin  of  the  thorax.  The  ele\'enth  and  twelfth  ribs  are 
attached  onl)'  by  their  posterior  extremities,  their  anterior  portion  being  imbedded  in 
the  soft  parts;  hence  they  are  called  floating  ribs.  The  ribs  slope  downward  and 
forward.  This  obliquity  increases  until  the  ninth  rib,  after  which  it  decreases.  The 
first  rib  in  front  corresponds  to  the  fourth  behind,  the  second,  third,  fourth,  fifth, 
sixth,  and  seventh  in  front  correspond  each  to  the  fourth  rib  lower  behind.  The  first 
rib  is  the  nearest  horizontal  in  regard  to  its  surface  and,  being  well  protected  by  the 
clavicle,  is  rarely  broken.  The  intercostal  spaces  are  broader  in  front  than  behind 
and  broader  above  than  below.      The  third  is  the  largest. 

The  groove  on  the  lower  surface  of  the  ribs  holds  the  intercostal  artery,  but  only 
as  far  back  as  the  angle,  from  which  point  it  occupies  the  middle  of  the  space. 

The  extent  of  the  intercostal  spaces  is  considerably  influenced  by  position — flexion 
of  the  body  brings  the  ribs  together,  extension  and  bending  to  the  opposite  side 
separates  them.  This  point  is  of  importance  in  reference  to  the  operations  of  para- 
centesis and  empyema. 

The  first  costal  cartilage  unites  directly  with  the  sternum,  there  being  no  joint 
present.  The  second  and  sometimes  the  third  cartilage  is  joined  to  the  sternum  by 
a  ligament  with  a  synovial  joint  above  and  below  it.      The  other  costal  cartilages  are 


THE   THORAX. 


I7S 


united  by  a  joint  witli  a  single  cavity.      These  joints  may  be  the  seat  of  metastatic 
abscesses  in  pysemic  infections. 

Cervical  ribs  spring  from  the  body  and  transverse  process  of  the  seventh 
cervical  vertebra.  They  may  be  long  enough  to  reach  to  the  sternum,  but  usually 
are  much  shorter.  One  case  of  this  affection  was  seen  by  the  writer  in  a  man 
twenty-seven  years  of  age.  There  was  an  abnormal  fulness  above  the  scapula 
posteriorly,  and  above  the  clavicle  anteriorly,  just  to  the  inner  side  of  the  external 
jugular  vein,  a  distinct  bony  process  could  be  felt.  This  did  not  move  with  the 
scapula  or  clavicle  but  did  move  somewhat  with  respiration.  A  skiagraph  showed 
it  to  be  attached  to   the    spine.      The   patient    was    seen    again   five    years  later, 


Fig.  198.- 


cal  rib  attached  to  the  right  side  of  the  seventh  cervical  vertebra. 


when  the  same  condition  of  affairs  existed,  with  the  e.xception  that  movement  on 
respiration  was  not  so  marked.  A  knowledge  of  the  possible  presence  of  a  cervical 
rib  is  important  in  diagnosis,  otherwise  it  may  be  thought  to  be  a  bony  or  malignant 
new  growth  and  treatment  advised  accordingly.  The  subclavian  artery  may  pass 
over  the  cervical  rib  abo^•e  and  may  have  its  circulation  seriously  interfered  with. 

Fracture  of  the  Ribs. — The  ribs  are  almost  always  broken  by  direct  violence; 
fractures  from  indirect  force,  as  from  coughing,  sneezing,  and  other  forms  of  muscular 
exertion,  are  rare.  Fracture  from  compression  of  the  chest  is  also  rare.  The  site  of 
the  fracture  is  most  frequently  on  the  anterior  portion  of  the  chest  and  not  the  sides 


Fig.  199. — Fractured  ribs;  fusion  of  callus. 

or  back.  The  fourth,  fifth,  sixth,  and  seventh  ribs  are  most  often  broken.  The  first 
rib  is  well  protected  from  direct  blows  by  the  clavicle.  Lane,  however,  has  shown 
that  it  can  be  broken  by  pressure  of  the  clavicle  when  the  shoulder  is  depressed. 
The  eleventh  and  twelfth,  being  floating  ribs,  are  rarely  broken.  The  twelfth  rib  is 
the  least  frequently  so.  In  one  case  we  saw  the  eighth,  ninth,  tenth,  eleventh,  and 
twelfth  all  broken  by  the  passage  of  a  wheel.  The  soft  parts  attached  to  the  frag- 
ments prevent  much  displacement,  but  there  is  always  some,  due  to  the  respiratory 
movements.  Hence  callus  is  always  present  and  it  may  be  so  abundant  as  to  join 
adjacent  ribs  (see  Fig.  199).  As  already  stated,  death  frequently  follows  fracture  of 
the  ribs  and  is  due  to  wounding  of  the  chest  contents.  Rarely  the  intercostal  arteries 
may  be  wounded  and  produce  hsemothorax.     Wounding  of  the  lung  is  frequent. 


176  APPLIED    ANATOMY. 

Emphysema  of  the  surface  of  the  body  may  ensue,  but  is  not  dangerous.  Pneumo- 
thorax, which  may  be  accompanied  by  infiltration  of  air  into  the  lung  tissue,  is  more 
dangerous,  favoring  collapse  of  the  lung.  The  object  of  treatment  is  to  keep  the 
chest-walls  from  moving.  This  is  accomplished  by  strapping  the  chest  with  adhesive 
plaster,  which  is  usually  laid  on  almost  in  the  direction  of  the  ribs:  but  as  the  chest 
moves  with  respiration,  the  ribs  rising,  and  as  they  slope  downward  and  forward,  I 
have  preferred  to  lay  the  straps  on  from  in  front  downward  and  backward,  this  tends 
to  prevent  the  ribs  from  rising  in  inspiration. 

THE   THORACIC    VERTEBRA. 

The  thoracic  or  dorsal  vertebrae  are  twelve  in  number  and  are  so  articulated 
with  one  another  as  to  form  a  single,  regular  curve  with  its  concavity  forwards  and 
convexity  backward.  Any  sudden  change  in  the  direction  of  the  curve  is  an  evidence 
of  disease;  this  is  seen  in  the  angular  curvature  of  Pott's  disease  or  caries  of  the 
spine.  The  ribs  are  connected  with  the  vertebrae  by  the  articulation  of  the  head  of 
the  rib  with  the  body  of  the  vertebra,  and  the  tubercle  of  the  rib  with  the  transverse 
process.  The  transverse  process  is  connected  with  the  body  by  the  pedicle  and  with 
the  spinous  process  by  the  lamina.  The  spinal  cord  is  exposed  in  operations  by 
removal  of  the  spinous  process  and  laminae,  hence  the  name  laminectomy. 

The  spinous  processes  are  the  guides  which  indicate  the  position  and  condition 
of  the  vertebras.  Their  tips  are  not  covered  by  muscles  but  lie  close  beneath  the 
skin  and  are  readily  felt  and  any  abnormality  detected.  In  the  normal  body  the 
grooves  on  each  side  of  the  spinous  processes  are  tilled  up  with  muscle,  but  in  certain 
diseases,  as  in  infantile  paralysis  and  lateral  curvature,  they  become  atrophied  and 
the  spine  becomes  twisted,  hence  on  the  convex  side  of  the  abnormal  lateral  curve, 
to  the  outer  side  of  the  spines,  the  projection  formed  by  the  transverse  processes  and 
tubercles  of  the  ribs  can  be  both  seen  and  felt. 

The  external  curve  formed  by  the  tips  of  the  spinous  processes  of  the  thoracic 
region  in  the  normal  person  is  not  so  great  as  is  the  curve  formed  by  the  anterior 
portion  of  the  bodies  of  the  thoracic  vertebrae.  This  is  because  the  spinous 
processes  at  the  upper  and  lower  portions  of  the  chest  project  out  almost  at  right 
angles  to  the  long  axis  of  the  body,  while  those  of  the  middle  portion  slope  down- 
ward. Hence  the  tips  of  the  spinous  processes  of  the  seventh  cervical,  first  dorsal, 
and  twelfth  dorsal  vertebrae  are  opposite  the  bodies  of  the  same  vertebrae,  while  the 
others  are  opposite  the  bodies  of  the  vertebrae  next  below.  (The  spine  will  be 
considered  more  at  length  in  the  section  devoted  to  the  Back. ) 

SOFT    PARTS. 

The  bony  thorax  is  lined  by  the  pleurae,  the  ribs  are  united  to  each  other  by 
the  intercostal  muscles,  and  over  all  are  muscles,  superficial  fascia,  and  skin.  In 
addition,  in  front  are  the  mammar^^  glands  and  behind  are  the  scapulae. 

The  Intercostal  Muscles  and  Arteries. 

The  intercostal  spaces  are  occupied  by  the  two  intercostal  muscles,  with  a  fascia 
above  them,  one  below,  and  one  between  them. 

The  external  intercostal  muscles  run  downward  and  forward.  They  begin  at 
the  tubercles  of  the  ribs  posteriorly  and  end  at  the  costal  cartilages  anteriorly. 
They  are  continued  forward  to  the  sternum  by  the  anterior  intercostal  membrane, 
formed  by  the  fusing  of  the  outer  and  middle  intercostal  fascias.  The  internal 
intercostal  muscles  go  downward  and  backward.  They  begin  at  the  sternum  and 
end  at  the  angles  of  the  ribs.  They  are  continued  to  the  spine  by  the  posterior 
intercostal  membrane,  formed  by  the  fusing  of  the  middle  and  internal  intercostal 
fascias.  The  intercostal  arteries  come  from  both  anteriorly  and  posteriorly.  The 
anterior  intercostals  come  from  the  internal  mammary  for  the  upper  five  or  six 
spaces  and  from  the  musculophrenic  artery  for  the  remainder.  They  arise  either 
as  a  single  trunk  or  as  separate  superior  and  inferior  branches.  At  first  they  are 
between  the  pleura  and   internal   intercostal   muscle,   but  they  soon  perforate   that 


THE   THORAX. 


177 


muscle  and  run  between  it  and  the  external  intercostal,  the  superior  branch  running 
along  the  lower  edge  of  the  rib  and  the  inferior  branch  running  along  the  upper 
edge  of  the  rib  below.  The  aortic  or  posterior  intercostal  arises  as  a  single  trunk 
which  passes  between  the  external  intercostal  muscle  and  the  pleura.  Arriving  op- 
posite the  angle  of  the  ribs  it  divides  into  superior  and  inferior  branches  which 
unite  with  those  from  the  internal  mammary  {arteria  mamniaria  interna). 

From  the  vertebrse  out  to  the  angle  of  the  ribs  the  intercostal  artery  lies  about 
midway  between  the  ribs,  hence  it  is  liable  to  be  wounded  in  paracentesis  if  the 
puncture  is  made  too  far  back.  It  is  for  this  reason  that  operations  for  draining  the 
pleui'ae  are  performed  anterior  to  the  costal  angles.  The  superior  intercostal 
branches  are  larger  than  the  inferior  ones.  They  run  under  the  lower  edge  of  the 
rib  above  the  space  and  are  therefore  protected  from  injury,  particularly  stab-wounds. 

In  opening  the  chest  for  empyema  it  is  best  to  go  about  midway  in  the  intercosal 
space  and  not  too  close  to  the  lower  edge  of  the  rib  on  account  of  the  liability  of  wound- 
ing the  superior  intercostal.  The  inferior  branch  is  usually  quite  small  and  causes 
no  serious  hemorrhage.     Intercostal  bleeding  may  cause  a  hsemothorax  if  the  wound  is 


L  aorta 
Poste 


intercostal  arteries 


Internal  mammary  artenes 

Fig,   200. — Course  and  distribution  of  the  intercostal  arteries. 

small.  It  may  be  controlled,  if  the  vessel  is  cut  in  performing  the  operation  of 
paracentesis  for  empyema,  by  clamping  with  hEemostatic  forceps.  If  these  are 
allowed  to  remain  on  a  few  minutes  the  bleeding  often  does  not  recur  on  their 
removal.  If  desired  a  ligature  can  be  applied.  If  it  is  undesirable  to  rely  on  the 
clamp  or  ligature  then  the  wound  may  be  firmly  packed  with  gauze  or  a  piece  of  gauze 
may  be  depressed  through  the  wound  into  the  pleural  cavity  and  then  stuffed  with 
more  gauze,  after  which  the  tampon  so  formed  is  pulled  firmly  outward  against  the 
bleedino-  tissues. 


Covering  the  chest  anteriorly  are  the  pedoi'alis  major  and  pectoralis  viinor 
inuscles.  The  serratns  anterior  imagnus)  winds  around  its  side  and  posteriori)'-,  above 
is  the  trapezius  and  below  the  latissimus  dorsi.  Beneath  them  are  the  erector  spina 
{sacrospinalis)  muscles  on  each  side  of  the  spinous  processes. 

The  pectoralis  major  muscle  arises  from  the  sternal  half  of  the  clavicle,  from 
the  sternum  and  costal  cartilages  as  low  as  the  sixth  or  seventh  rib,  and  from  the 


1 78  APPLIED    ANATOMY. 

aponeurosis  of  the  external  oblique  muscle  and  sheath  of  the  rectus  muscle.  It 
inserts  into  the  outer  lip  of  the  bicipital  groove.  It  is  to  be  noted  in  regard  to  this 
muscle  that  it  is  attached  only  to  the  inner  half  of  the  clavicle  and  that  the  clavicular 


Clavi  pectoral  fasc 


Acromial  branch 
Humeral  branch 
Cephali 
Coracoid  pro 
Deltoid 


Thoracic  branch 
Acromial  thoracic  artery 
Pectorahs  minor 


and  sternal  parts  are  separated  by  a  cleft.      When  removing  it  in  e.\cision  of  the 
breast  for  carcinoma  one  separates  the  muscle  by  passing  through  this    cleft  and 

detaching  the  part  below.  It  forms  the  anterior 
fold  of  the  axilla  and  by  following  this  fold  to  the 
chest-wall  it  leads  to  the  fifth  rib,  as  it  is  at  that 
1  lb  that  the  muscle  leaves  the  chest-wall. 

The  pectoralis  major  is  covered  by  the  pec- 
toral fascia.  When  in  removal  of  the 
female  breast  for  nonma- 
lignant  growths  the  breast 
is  raised,  the  muscle  be- 
neath is  seen  to  be  covered 
;  with  a  thin  fascia  continu- 

-^  ous  with  the  fascia  of  the 

axilla.  Beneath  the  pec- 
toralis major  is  the  clazd- 
pcctoral  fascia  continuous 
with  the  costocoracoid 
')  membrane  above  and  the 
.•  axillary  fascia  at  the  sides. 
The  pectoralis 
minor  passes  from  the 
third,  fourth,  and  fifth  ribs 
to  the  coracoid  process.  Its 
origin  is  v\-ell  forward  to- 
ward the  anterior  extremi- 
ties of  the  ribs  and,  as  it  is 
not  attached  so  low  on  the 
chest  as  is  the  pectoralis 
major,  it  is  hidden  by  the  latter  and  does  not  aid  in  forming  the  anterior  axillary  fold. 
This  muscle  is  frequently  removed  in  operations  for  carcinoma  of  the  mammary  gland. 


^^^ 


;  serratus  anterior  i 


THE   THORAX. 


179 


The  serratus  anterior  fmagnus)  muscle  (Fig.  202)  passes  from  the  side  of 
the  chest  to  the  vertebral  or  posterior  border  of  the  scapula,  arising  by  nine  or  ten 
digitations  from  the  eight  or  nine  upper  ribs,  the  second  having  two.  The  slip  arising 
from  the  sixth  rib  is  the  one  most  prominently  seen  on  raising  the  arm  away  from 
the  side,  it  passes  the  farthest  forward.  The  slips  into  the  fifth,  seventh,  and  eighth 
ribs  may  also  be  seen.     This  muscle  passes  across  the  axilla  from  in  front  backward, 


Stemomastoid 

'Splenius 

Levator  (anguli)  scapula 

Scalenus  medius 


Teres  major 


Latissimus  dorsi 


External  oblique 
Internal  oblique' 


Petit's  triangli 


Fig.  203. — Muscles  of  the  back. 


lying  on  the  chest-wall.  It  is  supplied  by  the  posterior  thoracic  nerve  from  the 
fifth,  sixth,  and  seventh  cervicals.  This  nerve  is  also  called  the  loiig  external 
respiratory  nerve  of  Bell.  The  internal  respiratory  nerve  is  the  phrenic,  which  comes 
from  the  third,  fourth,  and  fifth  cervical  nerves.  One  of  the  main  functions  of  this 
muscle  is  to  keep  the  scapula  applied  to  the  chest  and  to  aid  in  rotating  it  in  elevation 


i8o  APPLIED    ANATOMY. 

of  the  arm.  When  it  is  parah-zed  the  arm  cannot  be  raised  beyond  a  right  angle 
and  the  scapula  projects,  particularly  at  its  lower  angle  and  posterior  edge.  This 
condition  is  called  ' '  zcingcd  scapula. " 

The  trapezius  muscle  (Fig. 203)  has  the  shape  of  a  triangle,  its  apex  being  out 
on  the  acromion  process  and  its  base  in  the  median  line.  It  arises  posteriorly  from 
the  inner  third  of  the  superior  curved  line  of  the  occiput,  the  occipital  protuberance, 
lio-amentum  nuchfe,  and  the  spines  of  the  seventh  cervical  and  all  the  thoracic  vertebrae. 

It  inserts  into  the  outer  third  of  the  clavicle  and  the  acromion  and  spinous  proc- 
esses of  the  scapula.  It  aids  in  rotating  the  scapula  and  elevating  the  shoulder;  its 
paralysis  is  followed  by  marked  dropping  of  the  shoulder.  It  is  supplied  by  the 
spinal  accessory  nerve,  which  is  sometimes  injured  in  operations  for  tumors  in\-oh-ing 
the  posterior  cervical  triangle. 

The  latissimus  dorsi  muscle  arises  from  the  spinous  processes  of  the  lower  six 
thoracic  \'ertebrfe,  from  the  posterior  layer  of  the  lumbar  fascia,  the  outer  lip  of  the 
posterior  third  of  the  iliac  crest  and  by  digitations  from  the  lower  three  or  four  ribs. 
Sometimes  it  is  attached  to  the  angle  of  the  scapula.  It  unites  with  the  tendon  of  the 
teres  major  muscle  to  be  inserted  into  the  bottom  of  the  bicipital  groove  and  extends 
somewhat  higher  than  the  tendon  of  the  pectoralis  major.  A  bursa,  which  may 
become  inflamed,  sometimes  lies  between  the  muscle  and  the  inferior  angle  of  the 
scapula.     The  latissimus  dorsi  and  teres  major  muscles  form  the  posterior  axillary  fold. 

The  erector  spinse  (sacrospinalis)  muscle  lills  up  the  hollows  on  each  side  of 
the  spinous  processes.  As  the  various  muscular  bundles  are  inserted  into  the  vertebrae 
by  innumerable  small  tendinous  slips,  in  exposing  the  vertebrse  in  performing  lamin- 
ectomy it  is  necessary  to  cut  them  ^^•ith  a  knife  or  scissors.  One  should  not  attempt 
to  separate  them  by  blunt  dissection.  These  muscles  become  atrophied  in  cases  in 
which  the  spine  becomes  distorted. 

SURFACE  ANATOMY  OF  THE  THORAX. 

On  looking  at  the  chest  one  should  note  whether  or  not  it  appears  normal.  It 
may  show  the  rounded  form  of  emphysema  or  the  fiat  form  of  phthisis.  One  side 
may  be  larger  than  the  other,  suggesting  pleural  effusion.  The  intercostal  spaces 
may  be  obliterated,  indicating  the  same  condition.  This  may  be  local  instead  of  over 
the  whole  chest.  Note  whether  Harrison's  groove,  funnel  and  pigeon  breast,  or 
beading  of  the  ribs,  already  described,  are  present.  Aneurism  affecting  the  great 
vessels  may  cause  a  bulging  in  the  upper  anterior  portion,  and  cardiac  disease  may 
produce  marked  changes  in  the  apex  beat.  This  may  be  displaced  to  the  right  side 
by  pleural  effusion. 

The  cla\icle  belongs  to  the  shoulder-girdle  and  hence  will  be  described  \\ith  the 
upper  extremity.  Both  it  and  the  sternum  are  subcutaneous  and  can  readily  be  felt 
beneath  the  skin.  The  point  of  junction  of  the  first  and  second  pieces  of  the  sternum 
is  opposite  the  second  costal  cartilage.  It  forms  a  distinct  prominence,  which  is 
readily  felt  and  is  a  most  \'aluable  landmark.  It  is  called  the  angulus  sterni  or  angle 
of  Ludivig.  There  is  usually  a  palpable  depression  at  the  junction  of  the  second 
piece  of  the  sternum  and  xiphoid  cartilage. 

The  tip  of  the  xiphoid  or  ensiform  cartilage  can  be  felt  about  4  cm.  below  the 
joint  between  it  and  the  second  piece  of  the  sternum.  The  top  of  the  sternum  is  oppo- 
site the  lower  edge  of  the  second  thoracic  vertebra.  The  angulus  sterni  is  opposite 
the  fifth  vertebra,  the  lower  end  of  the  second  piece  of  the  sternum  is  opposite  the 
tenth,  and  the  tip  of  the  ensiform  cartilage  is  opposite  the  eleventh  thoracic  ver- 
tebra. There  is  usually  comparati\'ely  little  fat  over  the  sternum,  so  that  in  fat  and 
muscular  people  its  level  is  below  that  of  the  chest  on  each  side.  Above  its  upper 
end  is  the  suprasternal  notch  or  depression,  below  its  lower  end  is  the  infrasternal 
depression  or  epigastric  fossa,  sometimes  called  the  scrobicithis  cordis. 

With  the  upper  end  of  the  sternum  articulate  the  cla\^icles.  The  sternocla\icular 
joint  possesses  an  interarticular  cartilage  between  the  clavicle  and  the  sternum.  This 
separates  them  sufificienUy  to  allow  the  formation  of  a  distinct  depression,  which  can 
readily  be  felt.  From  the  sternum  to  the  acromion  process  the  clavicle  is  subcuta- 
neous.    Below  the  inner  end  of  the  clavicle  the  first  rib  can  be  often  seen  and  felt.    At 


THE    THORAX. 


i8i 


the  middle  of  the  cla\'icle  it  is  so  deep  from  the  surface  as  not  to  be  accessible  and 
here  the  second  rib  is  the  one  which  shows  just  below  the  clavicle.  In  children  the 
point  of  junction  of  the  cartilages  and  ribs  can  often  be  distinguished;  this  is  par- 
ticularly so  in  cases  of  rachitis. 

The  line  of  junction  between  the  body  of  the  sternum  and  the  ensiform  cartilage 
can  be  distinguished,  and  to  each  side  of  it  is  felt  the  cartilage  of  the  seventh  rib, 
the  last  that  articulates  with  the  sternum.  The  tenth  rib  is  the  lowest  which  is 
attached  anteriorly,  the  eleventh  and  twelfth  being  shorter  and  floating  ribs.  The 
intercostal  spaces  are  wider  anteriorly  than  posteriorly  and  the  third  is  the  widest. 

The  nipple  is  usually  in  the  fourth  interspace  or  on  the  lower  border  of  the  fourth 
rib  and  on  a  line  a  little  to  the  outer  side  of  the  middle  of  the  clavicle.  In  women  its 
position  is  variable,  owing  to  the  breasts  being  pendulous.  The  mammary  gland 
reaches  from  the  third  to  the  seventh  rib.  As  the  pectoralis  major  muscle  does  not 
arise  lower  than  the  sixth  rib  it  is  seen  that  the  mammary  gland  projects  beyond  it,  an 
important  fact  to  be  remembered  in  operations  for  removal  of  the  breast. 

Immediately  to  the  outer  side  of  the  upper  edge  of  the  pectoralis  major,  beginning 
at  the  middle  of  the  clavicle  and  below  it,  is  a  hollow.  This  is  the  interval  between 
the  pectoralis  major  and  deltoid  muscles.      At  its  upper  end  it  is  equal  in  width  to  one- 


Suprastemal 

Sternal  end  of  first 

Second  rib 


Space  between  deltoid 

Outer  end  of  cla.,..^ 
Coracoid  process 
'   *  :romioclavicular  ji 
Acromion  process 


Angle  of  sternu 
opposite 


Tip  of  ensiform  process 
Infrastemal  dep: 


id  pectoralis  major 


Fig.  204. — Surface  anatomy  of  the  thora.x. 


sixth  the  length  of  the  clavicle,  because  the  deltoid  is  attached  only  to  the  outer 
third  of  the  clavicle.  Immediately  beneath  the  edge  of  the  deltoid  muscle  and  about 
2.5  cm.  below  the  clavicle  is  the  coracoid  process.  On  abducting  the  arm  the  scapula 
is  rotated  and  the  serratus  anterior  muscle  is  put  on  the  stretch;  this  makes  its  four 
lower  serrations  visible.  The  serration  attached  to  the  fifth  rib  is  the  highest,  the 
sixth  is  the  most  prominent  and  extends  farthest  forward,  while  below  are  the  last 
two  attached  to  the  seventh  and  eighth  ribs.  The  operation  of  paracentesis,  or  tapping 
for  pleural  effusion,  is  most  often  done  in  the  sixth  interspace  in  the  midaxillary  line. 
This  will  be  about  on  a  level  with  the  nipple.  The  apex  beat  of  the  heart  is  felt  in 
the  fifth  interspace,  about  2.5  cm.  (i  in.)  to  the  inner  side  of  the  line  of  the  nipple. 

Running  down  behind  the  costal  cartilages  and  crossing  the  intercostal  spaces 
about  a  centimetre  from  the  edge  of  the  sternum  is  the  internal  mammary  artery. 
When  it  reaches  the  sixth  interspace  it  divides  into  the  superior  epigastric,  which 
goes  downward  in  the  abdominal  walls,  and  the  muscidophrejiic,  which  passes  to  the 
attachment  of  the  diaphragm  along  the  edge  of  the  chest. 

(  The  relations  of  the  organs  of  the  chest  to  the  surface  will  be  discussed  later. 
The  nervous  supply  to  the  surface  of  the  chest  is  of  interest  mainly  as  indicating  the 
probable  location  of  the  lesion  in  cases  of  fracture  of  the  spine,  and  it  will  be  described 
in  the  section  devoted  to  the  Back.) 


APPLIED  ANATOMY. 


THE  MAMMA  OR  BREAST. 

The  name  mammary  gland  is  often  given  to  the  breast,  yet  the  latter  is  composed 
not  only  of  glandular  tissue  but  also  of  fibrous  and  fatty  tissue,  with  the  usual  vessels, 
nerves,  and  lymphatics.  In  the  male  the  glandular  portion  is  undeveloped,  the  fat  is 
relatively  scanty,  and  the  breast  as  a  whole  is  insignificant  and  flat.  In  the  virgin 
female  adult  it  is  more  spheroidal.  Above  the  nipple  it  is  flattened  and  below  it  is 
rounded.  Its  general  shape  is  circular  and  it  covers  the  chest-wall  from  the  upper 
border  of  the  third  rib  to  the  sixth  interspace.  Laterally  it  reaches  internally  almost 
to  the  sternum  and  externally  it  overlaps  the  edge  of  the  pectorahs  major.  It  lies 
imbedded  in  the  superficial  fascia.  In  its  development  it  is  simply  a  modified  seba- 
ceous oland.  Beginning  by  a  finger-like  growth  from  the  skin  it  burrows  its  way  into 
the  superficial  fascia.  It  becomes  compound  and  sends  its  branches  in  various  direc- 
tions, especially  does  it  extend  deeper  until  finally  it  pushes  away  most  of  the  fat  and 


Lobule  of  gland-tissues 


Excretory  duct 


Lactiferous  duct 
Fig.  205.— The  secreting  structure  of  the  breast.    (Piersol.) 

rests  on  the  fascia  covering  the  pectoralis  major  muscle.  This  is  wh)-  we  find  almost  no 
adipose  tissue  beneath  the  gland  but  mostly  between  the  glandular  structure  and  the 
skin  and  around  its  edges.-  The  shape  of  the  virgin  breast  is  due  mamly  to  its  adipose 
tissue  and  not  to  its  glandular  structure.  In  those  who  have  borne  children  the  breasts 
become  enlarged,  lax,  and  pendulous.  After  lactation  is  completed  they  again 
retract  but  rarely  regain  their  former  shape.  During  lactation  the  fatty  portion  ot  the 
breast  may  disappear  and  leave  it  apparently  in  a  shriveled  condition,  yet  such  a  breast 
may  be  functionally  quite  active.  Therefore  the  size  of  the  breast  is  no  criterion  of  its 
milk-producing  powers.  .      j-   -j   j    • 

The  secreting  structure,  racemose  in  character,  is  divided  into  ten  to 
sixteen  lobules  each  of  which  has  its  duct.  These  lactiferous  ducts  begin  in  the 
acini  and  end  in  the  nipple.  Beneath  the  nipple  they  are  dilated,  each  forming  a 
sinus  or  ampulla.  While  the  shape  of  the  breast  is  regular  in  its  outline  the 
o-landular  tissue  is  not  so.  It  possesses  three  projections  or  cusps.  One  of  these 
projects  inward  nearly  or  quite  to  the  sternum,  while  the  other  two  project  toward 
the  axilla  and  side,  one  being  lower  than  the  other.      These  are  the  most  common 


THE    MAMMA   OR    BREAST. 


183 


Suspensory  band- 


directions  in  which  the  glandular  tissue  is  prolonged,  but  it  may  extend  farther 
than  usual  in  any  direction;  hence  the  wide  incisions  made  in  cases  of  carcinoma. 

According  to  H.  J.  Stiles  {Ed.  Med.  Jouim.,  1892,  p.  1099),  the  secreting 
structure  may  extend  posteriorly  into  the  retromammary  tissue  between  the  layers 
of  the  pectoral  fascia.  Anteriorly  it  is  prolonged  with  the  fibrous  tissue  {ligaments 
of  Cooper)  almost  to  the  skin. 

The  nipple,  located  below  and  to  the  inner  side  of  the  centre  of  the  gland, 
has  connected  with  it  some  circular  and  longitudinal  unstriped  muscular  fibres. 
The  longitudinal  ones  are  attached  to  the  lactiferous  ducts  and  serve  to  retract 
the  nipple,  the  circular  ones  to  erect  it.  Surrounding  the  nipple  is  the  areola. 
It  is  pink  in  the  virgin  and  about  2.5  cm.  in  diameter.  After  pregnancy  its  hue 
becomes  brownish.  The  tubercles  of  Montgomery  are  the  numerous  elevations 
found  on  the  areola.  They  are  more  or  less 
modified  sebaceous  glands  and  enlarge  during 
pregnancy.  As  they  secrete  a  milky  fluid,  they 
are  often  regarded  as  accessory  milk  ducts. 
There  is  no  fat  in  the  nipple  or  areola. 

The  fibrous  structure  of  the  gland 
envelops  the  adipose  and  glandular  tissue. 
It  is  simply  a  continuation  of  the  fibrous  septa 
of  the  superficial  fascia.  These  septa  are  at- 
tached to  the  skin  above,  envelop  and  pass 
between  the  fatty  and  glandular  lobules,  and 
form  a  thin  covering  for  the  under  surface  of 
the  gland.  The  breast  is  sometimes  spoken  of 
as  having  a  capsule,  but  that  simply  refers  to 
the  fibrous  tissue  just  described.  This  fibrous 
tissue  follows  largely  the  ducts,  hence  when 
affected  with  carcinoma  it  contracts  and  draws 
the  nipple  in.  This  forms  the  retracted  nipple 
of  that  disease.  The  fibres  that  go  to  the  skin 
have  been  named  the  ligaments  of  Cooper. 
The  fibrous  tissue  forms  a  net-work  in  the 
meshes  of  which  are  packed  the  glandular 
structure  and  fat-lobules.  It  is  this  which 
gives  the  firmness  and  shape  to  the  virgin 
breast.  In  lactation,  the  fibrous  tissue  softens 
and  stretches  to  accommodate  the  increase  in 
the  glandular  structure  and  this,  with  the  loss 
of  fat,  causes  the  breast  to  become  lax  and 
pendulous.  In  palpating  a  normal  breast  be- 
tween the  fingers  and  the  thumb,  this  firm- 
ness may  feel  like  a  foreign  growth;  hence 
this  method  of  examination  is  not  to  be  rehed 
on.  A  better  way  is  to  have  the  patient  re- 
cline, and  lay  the  fingers  flat  on  the  breast, 
compressing  it  on  the  chest-wall  beneath. 
This  flattens  the  glandular  structure  and  any  mass  can  be  more  surely  detected. 

The  fibrous  tissue  between  the  glandular  structure  and  the  pectoralis  beneath 
is  quite  thin  and  loose,  with  large  spaces  in  it  which  have  been  called  the  sub- 
mammary bursa.  Pus  readily  spreads  in  this  loose  submammary  tissue,  but  in  the 
gland  itself  only  with  difficulty. 

Blood  Supply. — The  breast  is  supplied  with  blood  from  above  by  the  pectoral 
branch  of  the  acromial  thoracic  artery,  v\-hich  lea\'es  the  axillary  artery  at  the  inner 
border  of  the  pectoralis  minor  muscle.  The  pectoral  branch  descends  between  the 
pectoralis  major  and  minor  and  anastomoses  with  the  intercostals  and  long  thoracic. 
It  sends  branches  through  the  pectoralis  major  muscle,  and  in  carcinoma  of  the  gland 
it  may  be  seen  much  enlarged  running  downward  on  the  chest-wall  beneath  the 
muscle.      From  the  inner  side  come  X\\&  perforating  branches  of  the  internal  mamina)y 


Fascial  envelope' 


Fig.  206. — Sagittal  section  of  man: 
Oman  who  had  never  borne  childii 
1  formalin.     (Piersol.j 


i84 


APPLIED    ANATOMY. 


artery  from  the  second  to  the  sixth  rib;  the  second,  third,  and  fourth  are  the  largest 
and  may  bleed  freely  in  detaching  the  pectoralis  major.  To  the  outer  side  and 
below  is  the  long  thoracic  artery,  also  called  the  e.xternal  mammary;  it  descends 
along  the  outer  edge  of  the  pectoralis  minor,  sending  branches  inward  around  the 
edge  of  the  pectoralis  major  to  the  mammary  gland.  The  intercostal  arteries  also 
contribute  somewhat  to  the  blood  supply  of  the  gland. 

Lymphatics. — The  breast  is  exceedingly  well  supplied  with  lymphatics. 
They  are  composed  of  a  deep  set  around  the  lobules  and  ducts,  and  a  superficial  set 
which  together  with  the  deep  lymphatics  forms  a  plexus  around  the  nipple  called  the 
subareolar  plexus.  They  drain  mainly  toward  the  axilla  into  the  lymph-nodes  along 
the  edge  of  the  pectoralis  major  but  also  communicate  with  the  nodes  around  the 
subclavian  artery  and  those  in  the  anterior  mediastinum  which  accompany  the  inter- 
nal mammary  artery. 

The  axillaiy  nodes  are  in  three  sets:  one  along  the  edge  of  the  pectoralis 
major  muscle  {pectoral  nodes),  another  further  back  along  the  anterior  edge  of  the 
scapula   {^scapular  7iodes),    and  a  third  following  the  course  of  the  axillary  artery 


Subscapular  node 


Anterior  pectoral   nodi 


Inferior  pectoral  nod 


Intermediate  node 


Subareolar  plexus 
over  mammary 
gland 


Fig.  207. — Lymphatics  of  the  breast.     (Poirier  and  Cun&.) 

{humeral  nodes).  In  addition  to  these  there  are  some  infraclavicular  or  subclavian 
nodes  between  the  deltoid  and  pectoralis  major  and  at  the  inner  edge  of  the  pectoralis 
minor  muscles;  these  are  comparatively  rarely  involved  primarily.  The  axillary 
nodes  are  continuous  and  communicate  with  the  subclavian  and  supraclavicular  nodes, 
and  these  latter  are  frequently  enlarged  subsequent  to  the  axillary  infection.  The 
anastomosis  of  the  lymphatics  across  the  median  line  has  been  thought  to  account 
for  the  occurrence  of  the  disease  in  the  opposite  breast  or  axilla.  As  shown  by 
Sappey,  some  if  not  all  of  the  lymphatics  of  even  the  sternal  portion  of  the  breast 
drain  into  the  axilla  and  not  into  the  anterior  mediastinum,  thus  accounting  for  the 
axillary  involvement  when  the  inner  portion  of  the  breast  is  affected.  These  five 
sets  of  nodes  communicate  with  each  other,  and  an)^  one  may  be  alone  involved. 
The  supraclavicular  set  do  not  become  involved  primarily  because  no  vessels  run 
directly  from  the  breast  to  them ;  they  are  affected  secondarily  to  involvement  of  the 
axillary  or  subclavian  sets. 

The  deep  lymphatics  of  the  breast,  according  to  Sappey,  follow  the  ducts  to  the 
areola,  there  anastomosing  with  the  superficial  lymphatics  to  form  what  he  called  the 
sjibareolar plexus,  which  drains  by  two  trunks  into  the  axilla.     The  lymphatics  of  the 


THE    MAMMA    OR    BREAST  185 

breast  anastomose  with  those  of  the  surrounding  structures;  hence  in  certain  cases  the 
pectoralis  muscles  and  even  the  pleura  may  be  affected,  and  when  the  disease  is  widely 
disseminated  by  the  lymph-channels  on  the  chest-walls  there  is  produced  the  thick- 
ened, brawny,  infiltrated  condition  known  as  the  cancer  "  c«  cuirasse"  of  Velpeau. 
Nerves. — The  breast  and  the  skin  over  it  are  supplied  from  the  descending 
branches  of  the  cervical  plexus,  by  thoracic  branches  from  the  brachial  plexus,  and 
by  the  second,  third,  fourth,  fifth,  and  sixth  intercostals.  These  are  not  of  so  much 
practical  importance  as  the  lateral  branches  of  the  second  and  third  intercostal 
nerves.  That  of  the  second  is  called  the  intercostobrachialis  (^humeral)  nerve;  it 
crosses  the  axilla,  anastomoses  with  the  medial  brachial  (lesser  internal)  cutaneojLS 
nei've,  and  supplies  the  skin  of  the  inner  and  upper  portion  of  the  arm.  The  third 
intercostal  anastomoses  with  the  second  and  gives  a  branch  to  the  arm  and  to  the 
dorsum  of  the  scapula.  These  nerves  are  certain  to  be  seen  in  clearing  out  the  axilla. 
Their  division  is  accompanied  by  no  paralysis,  but  disturbance  of  them  accounts  for 
some  of  the  pain  and  discomfort  following  the  operation. 

Abscess  of  the  Breast. 

Suppuration  in  the  mammary  gland  is  usually  due  to  infection  which  has 
entered  the  gland  either  through  the  lymphatics  or  the  lactiferous  ducts.  The 
starting  point  of  the  infection  is  thought  to  be  an  ulcerated  crack  or  fissure  of  the 
nipple.  Infection  travelling  into  the  gland  by  way  of  the  lymphatics  would  cause 
pus  primarily  in  the  pericanalicular  tissue  but  it  would  soon  involve  the  lactiferous 
ducts  and  then  pus  might  exude  from  the  nipple.  Infection  travelling  up  the  ducts 
might  reach  the  ultimate  lobules  and  therefore  give  rise  to  widespread  and  multiple 
abscesses.  Suppuration  in  this  gland  resembles  that  in  the  parotid  gland,  already 
described.  When  the  body  of  the  gland  is  involved  it  is  apt  to  be  so  in  more  than 
one  spot.  The  infection  follows  the  branching  of  the  ducts  and  usually  there  are 
several  small  abscesses  instead  of  one  large  one.  If  there  is  a  large  collection  of  pus 
it  is  not  contained  in  one  cavity  but  more  likely  in  several.  This  is  so  often  the  case 
that  in  treating  these  abscesses  it  is  advised  that  they  should  not  only  be  incised  but 
the  finger  should  then  be  introduced  and  the  partitions  separating  the  various  abscess 
cavities  broken  through. 

In  its  incipiency  a  lymphatic  infection  may  cause  a  single  collection  of  pus,  but 
this  soon  breaks  through  into  the  canaliculi  and  infects  and  involves  the  glandular 
structure.  In  an  early  stage  of  duct  infection  several  inflammatory  areas  may  start 
up  about  the  same  time.  The  pus  soon  breaks  through  the  canaliculi  and  involves 
the  periglandular  tissue  so  that  in  each  mode  of  infection  the  condition  soon  becomes 
the  same.  It  is  for  this  reason  that  it  is  difficult  to  say  whether  the  infection  origi- 
nated in  the  lymphatics  or  the  ducts. 

When  the  ducts  are  inflamed  the  pus  often  finds  a  vent  at  the  nipple.  The  fre- 
quency of  this  is  the  reason  why  direct  infection  of  the  ducts  is  regarded  as  the  more 
common  mode.  In  incising  a  mammary  abscess  the  incisions  should  follow  the  course 
of  the  ducts,  that  is,  they  should  be  made  in  a  direction  radiating  from  the  nipple  towards 
the  circumference  and  not  trans\'ersely,  otherwise  healthy  ducts  will  be  divided. 

Submammary  Abscess  (for  subpectoral  abscess  see  page  264). — As  has  been 
pointed  out  some  of  the  glandular  tissue  dips  down  to  the  pectoral  fascia,  hence 
when  some  of  these  deepest  lying  lobules  are  inflamed  the  pus  instead  of  breaking 
laterally  into  the  adjoining  lobules  or  tissue  breaks  into  the  submammary  tissue  and 
bursa.  Here  it  spreads  rapidly  beneath  the  gland  and  raises  the  gland  above  it. 
As  the  pus  accumulates  it  sinks  downward  and  works  its  way  outward  to  the  lower 
outer  quadrant  along  the  edge  of  the  anterior  axillary  fold.  Here  is  where  it  should 
be  opened.      As  the  cavity  is  single  one  incision  is  sufficient  to  drain  it. 

Tumors  of  the  M.\mmary  Gland. 

Benign  Tumors. — There  are  two  main  kinds  of  benign  mammary  growths, 
cystic  and  adenomatous  or  fibro-adenomatous. 

Cystic  growths  due  to  retention  of  secretion  of  the  ducts  occur  as  small,  rounded 
tumors,  painful  and  tender  to  the.  touch,  and  are  seen  between  the  ages  of  25  and  35 


1 86  APPLIED    ANATOMY. 

years.  They  are  not  in  any  way  dangerous.  They  are  composed  of  a  number  of 
dilated  acini.  Another  form  is  degenerative  in  character,  occurring  in  the  decline  of 
life,  and  consists  of  a  large  number  of  various  sized,  usually  small,  cysts  located 
mostly  toward  the  deep  surface  of  the  gland.  They  contain  mucoid  and  degenerated 
material  produced  by  the  lining  membrane  of  the  acini.  The  whole  breast  is  apt  to 
be  studded  with  small  shot-like  cysts  and  both  breasts  are  usually  in\'olved.  This 
affection  in  itself  is  not  malignant,  but  it  may  become  so  by  intracanalicular  growths 
springing  up  from  the  walls  of  the  cysts. 

AdeJiomatoHS  growths  are  encapsulated,  usually  single,  and  are  composed  of 
three  distinct  elements.  These  are  glandular  tissue  more  or  less  normal  in  character, 
glandular  tissue  cystic  in  character,  and  fibrous  tissue.  The  fibrous  tissue  forms  the 
capsule  as  well  as  the  stroma  in  the  meshes  of  which  latter  glandular  tissue,  nearly 
normal,  occurs.  These  are  called  fih-o-adenomata  and  if  the  glandular  tissue  is 
quite  abundant  they  may  be  called  adenomata.  If  the  glandular  acini  are  dilated 
so  as  to  overshadow  the  fibrous  portion,  then  it  is  called  a  cystic  adenoma.  These 
cystic  growths  may  be  quite  large. 

Malignant  Tumors. — The  malignant  growths  of  the  breast  are  either  sarco- 
mata or  carcinomata. 

Sarcomata  originate  from  the  fibrous  stroma  of  the  breast  surrounding  the  ducts 
and  acini.  As  it  increases  in  size  it  may  irritate  the  glandular  structure  and  obstruct 
the  ducts,  thus  forming  cysts  which  may  be  quite  large.  Such  a  growth  has  been 
called  a  cystic  sarcoma.  It  also  shows  itself  as  a  single  tumor,  which  may  be  large 
but  solid.  The  lymph-nodes  are  rarely  affected.  The  disease  when  it  wanders 
from  the  seat  of  the  primary  growth  shows  itself  in  some  of  the  internal  organs.  It 
is  disseminated  by  the  blood  and  not  by  the  lymphatics. 

Carcinomata  originate  from  the  epithelium  lining  the  ducts  and  acini.  For  our 
purposes  we  may  divide  them  into  two  classes,  those  that  grow  into  the  ducts  {i7itra- 
canaliciilar)  and  those  that  break  through  the  ducts  and  invade  the  surrounding 
tissues,  of  these  scirrhus  is  the  type. 

Intracanalicular  growths  have  by  many  authors  been  considered  nonmalignant  on 
account  of  the  rarity  of  their  producing  general  infection.  They  grow  at  times  rapidly 
and  produce  tumors  of  considerable  size.  On  section  they  contain  many  cysts  and 
into  these  cysts,  which  are  derived  from  the  dilated  milk-ducts,  protrude  outgrowths 
from  the  walls.  Sometimes  the  cavity  of  the  cyst  has  its  liquid  contents  replaced  by 
the  solid  tumor  which  has  grown  into  it.  A  discharge  of  bloody  serum  from  the 
nipple  is  common  in  these  growths. 

Scirrhus  is  the  ordinary  form  of  cancer  of  the  breast.  It  starts  in  the  epithelial 
structures  of  the  gland,  breaks  through  the  basement  membrane  and  involves  the 
structures  immediately  adjacent  to  it,  and  is  disseminated  more  widely  by  the  lym- 
phatics. Paget  s  disease  is  a  true  carcinoma  which  begins  as  an  eczema  or  ulceration 
around  the  nipple  and  later  becomes  disseminated. 

Carcinoma  follows  the  gland  structure,  and  readily  involves  the  pectoral  fascia 
covering  the  pectoralis  major  muscle.  Anteriorly,  the  gland  structure  in  places 
follows  the  ligaments  of  Cooper  to  the  skin  above,  hence  the  frequency  with  which 
the  skin  is  involved. 

The  scirrhus  variety  does  not  involve  the  ducts  in  the  same  manner  as  does  the 
intracanalicular  variety,  hence  bloody  discharges  from  the  nipple  are  not  so  common 
as  in  that  affection.  The  disease,  when  affecting  the  region  of  the  nipple,  has  been 
considered  more  dangerous  because  of  the  greater  development  of  the  lymphatics, 
particularly  the  subareolar  plexus  of  Sappey,  at  that  point. 

Carcinomatous  disease  extends  especially  by  way  of  the  lymphatics.  These 
follow  the  fibrous  and  canalicular  structure,  therefore  on  section  the  cancerous  tissue 
can  be  seen  extending  like  roots  into  the  surrounding  gland.  This  tissue  shrinks, 
contracts,  and  becomes  harder  as  the  disease  progresses,  that  is  why  retraction  of  the 
nipple  and  dimpling  of  the  skin  occurs.  The  most  free  lymphatic  drainage  occurs 
toward  the  axilla,  not  toward  the  mediastinal  nodes.  The  first  nodes  to  show  infec- 
tion are  those  lying  along  the  edge  of  the  pectoralis  major  muscle  about  the  level  of 
the  third  rib.  Later,  the  nodes  at  the  anterior  edge  of  the  scapula  accompanying  the 
subscapular  artery  become  involved,  or  those  along  the  axillary  vessels.      Still  later 


THE    MEDIASTINUM.  187 

those  along  the  subclavian  vessels  may  be  enlarged  and  may  be  felt  above  the  clavicle 
and  farther  inward  behind  the  sternomastoid  muscle  low  down. 

In  rare  instances  the  disease  may  be  carried  superficially  to  the  subclavian  nodes 
in  the  infraclavicular  triangle  between  the  deltoid  and  pectoralis  major  muscles. 
Should  the  disease  spread,  it  may  be  carried  by  the  lymphatics  to  the  opposite  breast 
directly  across  the  median  line.  If  it  involves  the  lymphatics  of  the  chest-wall  gen- 
erally there  is  produced  the  brawny  condition  of  the  skin  called  cancer  ' '  en  aiirasse ' ' 
of  Velpeau  already  alluded  to.  A  cancerous  nodule  beyond  the  edge  of  the  pectoralis 
major  muscle  is  not  necessarily  an  enlarged  node,  but  may  be  due  to  the  involvement 
of  one  of  the  cusps  of  the  gland,  which  sometimes  extend  even  into  the  axilla. 

Removal  of  the  Cancerous  Breast. — The  origin  of  cancer  is  now  believed 
to  be  local  and  not  general  and  the  more  complete  its  removal  the  greater  is  the 
likelihood  of  cure.  Therefore  every  effort  is  made  to  excise  every  possible  infected 
tissue.      This  has  led  to  the  performance  of  very  extensive  operations. 

The  incision  is  made  so  large  as  to  include  nearly  or  quite  all  of  the  skin 
covering  the  glandular  tissue;  this  is  because  of  the  intimate  connection  of  the 
two,  as  already  pointed  out.  It  is  carried  out  to  the  arm;  this  is  to  facilitate 
clearing  out  the  axilla  and  all  its  contents.  The  incision  is  kept  close  to  the  skin; 
this  is  to  avoid  any  glandular  structure  which  may  possibly  be  beneath.  The 
pectoral  fascia  covering  the  pectoral  muscle  is  always  removed. 

Often  both  the  pectoralis  major  and  minor  muscles  are  removed.  In  excising 
them  the  slight  interspace  between  the  clavicular  and  sternal  fibres  of  the  pectoralis 
major  muscle  is  entered  and  the  muscle  detached  from  the  anterior  extremities 
of  the  ribs  and  sternum.  In  so  doing  the  anterior  intercostal  arteries,  particularly 
those  of  the  second,  third,  and  fourth  spaces,  are  liable  to  bleed  freely.  As  the 
pectoralis  major  is  detached  and  turned  outward,  the  acromial  thoracic  artery  is 
seen  at  the  inner  edge  of  the  pectoralis  minor  muscle  with  its  pectoral  branch 
running  down  the  surface  of  the  chest.  This  may  be  ligated,  the  finger  slipped 
beneath  the  pectoralis  minor,  and  this  muscle  cut  loose  from  the  coracoid  process 
above  and  the  third,  fourth,  and  fifth  ribs  below.  At  this  stage  some  operators 
clear  the  subclavian  and  axillary  vessels  of  all  loose  tissues  and  lymph-nodes. 

The  vessels  are  followed  out  on  the  arm.  When  the  insertion  of  the  pecto- 
ralis major  is  reached  it  is  detached  and  the  whole  mass  turned  outward  and  pared 
loose  along  the  anterior  edge  of  the  scapula.  Thus  it  is  removed  in  one  piece. 
The  part  of  the  chest-wall  which  has  been  cleared  of?  embraces  from  the  middle 
or  edge  of  the  sternum  to  the  anterior  edge  of  the  scapula  and  from  near  the 
lower  edge  of  the  chest  below  to  the  clavicle  above.  The  vessels  have  been 
cleared  off  from  the  insertion  of  the  axillary  folds  on  the  arm  to  underneath  the 
clavicle.  Many  operators  make  an  additional  incision  above  the  clavicle  and  clear 
out  the  supraclavicular  fossa  even  if  no  enlarged  glands  can  there  be  detected. 
Sometimes  the  long  thoracic  artery  and  thoracicalis  longus  (long  external  thoracic) 
nerve  may  be  wounded,  but  they  need  not  be. 

Two  nerves  will  be  seen  crossing  the  axilla  from  the  chest  to  the  arm.  They 
are  the  lateral  branches  of  the  second  and  third  intercostal  nerves.  The  second  is 
called  the  intercostobrachialis  (humeral)  nerve.  If  they  can  conveniently  be  spared 
it  is  to  be  done,  otherwise  they  are  di\ided.  In  clearing  the  axillary  vessels,  small 
veins  and  even  arteries  may  be  divided  close  to  the  main  trunks.  These  may 
be  expected  to  bleed  freely  but  are  usually  readily  secured.  Care  should  be  taken 
not  to  wound  unnecessarily  the  subscapular  artery  and  particularly  the  vein  as  they 
wind  around  the  anterior  edge  of  the  scapula  2  to  3  cm.  below  its  neck.  Some  operators 
prefer  to  detach  the  breast  from  without  in  instead  of  from  within  out  as  described. 

THE  MEDIASTINUM. 

The  mediastinum  is  the  middle  space  of  the  chest  between  the  spine  behind,  the 
sternum  in  front,  and  the  pleura;  to  each  side.  It  is  subdivided  into  a  superior 
mediastinum,  which  is  the  part  above  Ludwig's  angle,  between  the  first  piece  of  the 
sternum  in  front  and  the  vertebra;  from  the  first  thoracic  to  the  upper  portion  of  the 
fifth  behind.  The  part  below  is  divided  into  the  anterior  mediastinum,  the  middle 
mediastinum,  and  x\\^ posterior  mediastinum. 


i88  APPLIED    ANATOMY. 

Superior  Mediastinum. — The  upper  level  of  the  superior  mediastinum  is 
oblique,  as  it  runs  from  the  upper  edge  of  the  sternum  to  the  first  thoracic  vertebra. 
The  lower  level  of  the  superior  mediastinum  runs  from  the  junction  of  the  first  and 
second  pieces  of  the  sternum  to  the  upper  border  of  the  fifth  { or  lower  border  of  the 
fourth  )  thoracic  vertebra.    Laterally  it  is  bounded  by  the  pleurae  and  apices  of  the  lungs. 

The  distance  from  the  anterior  sui'face  of  the  spine  to  the  posterior  surface  of  the 
sternum  is  quite  small,  being  only  5  to  6  cm.  (2  to  2}^  in.).  Through  this  pass 
most  important  structures.  The  trachea  and  asophagiis  are  in  the  median  line  as  well  as 
the  remains  of  the  thymus  gland.  To  each  side  are  the  great  vessels,  the  innominate 
artery  being  onthe  right  and  the  subclavian  and  carotid  on  the  left.  The  left  innomi- 
nate vein  crosses  transversely  just  below  the  top  of  the  sternum  to  meet  the  innominate 
vein  of  the  right  side  and  form  the  superior  vena  cava.  Into  the  innominate  veins 
empty  the  inferior  thyroid,  vertebral,  superior  intercostal,    internal  mammary,  and 


Innominate  arten' 
Left  innominate 
Arch  of  aorta- 


Sternum 
Ascending:  aorta 


Fig.  208. — The  superior  (red),  anterior  (blue),  middle  (yellow),  and  posterior  (green),  mediastina. 
(Modified  from  Piersol.) 

pericardial  veins  ;  and  into  the  descending  vena  cava  empties  the  vena  azygos  major. 
On  the  posterior  surface  of  the  cesophagus  and  afterwards  to  its  left  side  passes  the 
thoracic  duct.  The  trachea  bifurcates  opposite  the  junction  of  the  first  and  second 
pieces  of  the  sternum,  and  the  transverse  portion  of  the  arch  of  the  aorta  rises  as  high 
as  the  middle  of  the  manubrium.  The  phrenic  nerves  lie  against  the  pleura,  the 
right  having  the  vena  cava  to  its  inner  side. 

The  right  vagus  {pneiimogastric')  nerve  comes  down  between  the  innominate 
artery  and  vein  and  passes  downward  on  the  posterior  surface  of  the  oesophagus.  It 
gives  its  recurrent  laryngeal  branch  off  at  about  the  right  sternoclavicular  joint. 
The  left  vagus  nerve  comes  down  to  the  outer  side  of  the  left  carotid  artery  and 
goes  over  the  arch  of  the  aorta,  giving  off  its  recurrent  laryngeal  branch,  and  thence 
proceeds  to  the  anterior  surface  of  the  cesophagus.      The  presence  of  the  trachea  in 


THE    MEDIASTINUM.  189 

the  median  line  and  the  edges  of  the  lungs  which  meet  opposite  the  second  rib  give 
a  resonant  percussion  note  to  the  first  piece  of  the  sternum.  With  all  these 
important  structures  crowded  in  the  small  space  between  the  vertebrse  and  sternum 
it  is  easy  to  see  why  tumors  in  this  region  should  cause  serious  symptoms. 

Aneurism  in\-ol\'ing  the  arch  of  the  aorta  and  the  great  vessels  is  common. 
Tumors,  such  as  sarcoma,  carcinom.a,  and  glandular,  though  rare,  do  occur. 
Abscess  from  high  dorsal  Pott's  disease  has  been  known  to  cause  serious  effects. 

The  svmptoms  of  all  these  affections  resemble  one  another  to  a  considerable 
extent.  Interference  with  the  blood-current,  usually  in  the  veins,  almost  never  in 
the  arteries,  is  marked.  Alteration  in  the  \-oice  is  produced  by  pressure  on  the 
recurrent  larjmgeal  nerves.  Dvspncea  from  the  pressure  on  the  trachea  and  difh- 
culty  in  swallowing  also  occur,  as  well  as  interference  with  the  circulation  and  the 


Vagus  nerve 
■Internal  jugular  vein 

carotid  artery 
Subclavian  ' 

Left  innominate 

Phrenic  i 

Subclavian  artery 
Vagus  nerve 


Descending 
I  cava 
Left  pulmonary 
artery- 
Left  bronch' 


Right  ventricle 


Fig.  2og. — Conte 


ved  from  the   front. 


action  of  the  heart.      The  presence  of  growths  in  this  region  is  indicated  also  by  the 
presence  of  dulness  over  the  region  of  the  manubrium. 

Anterior  Mediastinum. — This  is  the  space  below  the  second  costal  cartilages, 
between  the  sternum  in  front,  the  pericardium  behind,  and  the  two  pleurae  on  the 
sides.  It  is  only  a  narrow  slit  in  the  median  line  above  from  the  second  to  the 
fourth  costal  cartilage;  from  here  the  right  pleura  is  prolonged  obliquely  down  and 
outward  to  the  seventh  costal  cartilage,  ^\^hich  it  follows.  On  the  left  side  the  pleura 
leaves  the  median  line  about  the  fourth  cartilage  and  passes  out  about  2  cm.  to  the 
left  of  the  sternum  and  then  down  to  the  seventh  costal  cartilage,  which  it  follows. 
The  triangularis  sterni  muscle  arises  from  the  under  surface  of  the  lower  third  of  the 
sternum  and  from  the  xiphoid  cartilage  and  passes  upward  and  outward  to  insert 
into  the  costal  cartilages  of  the  second  to  the  sixth  ribs  inclusive.  The  vniscle  lies 
in  front  of  the  anterior  mediastinum  and  the  internal  mammary  artery  runs  down 
between  ft  and  the  bone  about  i  cm.  distant  from  the  edge  of  the  sternum.  There 
are  a  few  lymphatic  nodes  in  the  anterior  mediastinum  on  the  diaphragm  below  and 


I  go 


APPLIED    AXATOMY. 


in  the  superior  mediastinum  on  the  arch  of  the  aorta  and  left  innominate  vein  above. 
A  chain  of  nodes  also  accompanies  the  internal  mammar\'  artery  along  the  edge  of 
the  sternum  between  the  pleura  and  chest  wall. 

Adscess  of  the  anteiior  mediastinum  inav  result  from  infection  due  to  injur}'  or 
punctured  wounds.  It  may  break  into  the  pleurae  on  the  sides,  into  the  pericar- 
dium posteriori}",  work  its  wa}'  down  toward  the  abdomen,  or  point  in  the  intercostal 
spaces  at  the  edge  of  the  sternum. 

Payacentesis pericardii  is  performed  in  the  sixth  interspace  close  to  the  sternum; 
also,  the  fifth  and  sixth  cartilages  may  be  resected,  the  internal  mammarj'  artery 
ligated,  and  the  pericardium  opened  and  even  drained. 

If  one  attempts  to  pass  a  trochar  into  the  pericardium  b}'  a  puncture  through* 
the  fifth  or  sixth  interspace  sufficiently  far  out  to  avoid  wounding  the  internal 
mamman,-  arten,'  the  pleura  is  apt  to  be  wounded,  as  it  passes  farther  toward  the 
median  line  than  does  the  lung. 

The  Middle  Mediastinum. — The  middle  mediastinum  is  limited  in  front  by 
the  anterior  ^^all  of  the  pericardium  and  behind  by  the  posterior  wall  of  the  pericar- 
dium and  roots  of  the  lungs.  It  contains  the  heart  -with  the  lower  half  of  the  descend- 
ing vena  cava  and  the  vcyia  azygos  major  emptying  into  it,  and  the  ascending  aorta; 


zygos  major 
^  -Right  bronchus 

- — -Right  pulmonarj-  artery 
^  Pulmonary  vein 


Thoracic  due 
Phrenic 
Recurrent  iar\Tigeal  nerve 


Bronchial  artery.^ 

Pulmonary  artery— _. 

Left  vagus 

Left  bronchus- 


Pulm 


l-on     1  c  -car. 


also  the  structures  forming  the  roots  of  the  lungs,  viz. ,  the  right  and  left  brojichi, 
and  xhe  pulmonaiy  arteries  and  veins.'^-  The  phrenic  nerves  lie  between  the  pericar- 
dium and  pleurse  anteriorlv. 

The  bronchial  lymphatic  nodes  are  numerous  between  the  structures  forming  the 
roots  of  the  lungs.  It  is  these  nodes  that  are  so  often  enlarged  in  diseases  of  the 
lungs.  They  are  affected  in  malignant  disease  as  well  as  in  tuberculosis,  etc.  Enlarge- 
ments of  the  heart  pressing  on  the  vessels,  particularly  the  vena  azygos  major,  are 
sometimes  thought  to  cause  pleural  effusions,  especiallv  if  one-sided. 

VV'hen  the  pericardium  is  distended  with  fluid  it  enlarges  more  in  an  up  and  down 
direction,  but  when  the  heart  is  enlarged  its  size  increases  mainly  laterally — from  side 
to  side. 

Posterior  Mediastinum. — The  posterior  mediastinum  extends  from  the  peri- 
cardium and  roots  of  the  lungs  anteriorly  to  the  vertebrae  posteriori}-.  The  pleurae 
are  on  each  side.  Behind  the  pericardium  runs  the  (esophagus,  lying  in  front  of  the 
aorta,  which  rests  on  the  vertebrae.  In  the  chink  between  the  aorta  and  bodies  of 
the  vertebrae  lies  the  thoracic  duct  and  immediately  to  its  right  side  is  the  veiia  azygos 

*  The  mediastina  are  arbitrarj?  di\-isions,  and  it  is  a  question  as  to  whether  the  roots  of  the 
lungs  should  not  be  included  in  the  posterior  instead  of  the  middle  mediastinum. 


THE    MEDIASTINUM.  191 

■major.  The  vena  asygos  minor  is  on  the  left  side  of  the  vertebrae  and  crosses  the 
sixth  to  join  the  vena  azygos  major.  The  descending  thoracic  aorta  is  not  infrequently 
the  seat  of  aneurism. 

Mediastinal  Tumors. — Cancer  is  the  most  frequent  malignant  new  growth,  then 
sarcoma  and  lymphoma.  Great  enlargement  of  the  lymph-nodes  occurs  in  Hodgkin  's 
disease  and  is  probably  a  factor  in  causing  a  fatal  issue.  Enlargements  also  result 
from  tuberculosis  and  other  diseases.  They  give  rise  to  pressure  symptoms.  Dyspnoea 
may  be  due  to  pressure  on  the  trachea  or  heart  and  great  vessels.  The  circulation 
may  be  so  much  impeded  that  the  enlargement  of  the  collateral  veins,  especiall)'  those 
of  the  surface,  may  be  very  marked.  There  may  also  be  difficulty  of  swallowing  due 
to  pressure  on  the  oesophagus. 

Pleural  EfTusions. — Serous  effusions  into  the  pleurae  are  also  known  to  accom- 
pany heart  disease  and  have  been  attributed  in  some  instances  to  obstruction  of  the 
circulation.  They  are  apt  to  be  unilateral  and  are  most  often  found  affecting  the 
right  pleural  cavity.  Baccelli  attributed  the  eff'usion  to  obstruction  of  the  blood 
current  through  the  vena  azygos  major  ;  the  enlarged  heart  pulling  the  superior  \ena 
ca\'a  down  drew  the  vena  azygos  major  tightly  over  the  right  bronchus,  as  is  well 
shown  in  Fig.  210.  Steele  (Univ.  Med.  Mag.,  i^q"]  \  Journ.  Ani.  Med.  Asso.,  1904) 
and  Stengel  (  Wniv.  Penna.  Med.  Bulletin,  1901)  held  that  the  dilated  right  heart  by 
extension  upward  e.xerts  pressure  on  the  root  of  the  right  lung  and  indirectly  pinches 
the  azygos  major  vein  as  it  curves  over  the  right  bronchus  to  enter  the  superior 
vena  cava.  Fetterolf  and  Landis  {Am.  Journ.  Med.  Sciences,  1909)  believe  that 
the  fluid  comes  from  the  \'isceral  pleura  and  not  from  the  parietal  pleura,  and  that  the 
outpouring,  so  far  as  the  pressure  factor  is  concerned,  is  caused  by  dilated  portions 
of  the  heart  pressing  on  and  partly  occluding  the  pulmonary  veins.  They  point  out 
that  Miller  (Am.  Journ.  of  Ajiat. ,  vii)  has  shown  that  the  veins  draining  the  visceral 
pleura  empty  into  the  pulmonary  veins  ;  therefore,  if  these  latter  are  obstructed, 
transudation  may  ensue  ;  this  may  occur  on  either  side.  They  point  out  that  if  the 
right  atrium  (auricle)  dilates,  it  expands  upward  and  backward  and  compresses  the 
left  auricle  and  root  of  the  right  lung;  and  of  the  parts  composing  the  root  the 
pulmonary  veins  are  the  most  anterior,  and,  therefore,  the  ones  most  liable  to  be 
compressed.  Left-sided  effusions  are  accounted  for  by  compression  of  the  left 
pulmonary  vein  by  the  dilated  left  atrium  (which  is  the  most  posterior  of  the  four 
chambers)  and  its  appendi.x.  The  greater  frequency  of  right-sided  effusions  is  due 
to  the  more  common  occurrence  of  dilatation  of  the  right  side  of  the  heart. 


192 


APPLIED    ANATOMY. 


THE   CHEST   CONTENTS. 

For  the  sake  of   convenience   in  description   and   record,  the   chest  has  been 
di\ided  into  various  regions  and  marked  by  certain  longitudinal  lines. 

The    Longitudinal    Lines. 

Seven  longitudinal  lines  are  used.     They  run  parallel  with  the  long  axis  of  the  body. 

1.  The  median  line   means  the  midline  of    the  body.      This  runs  down  the* 
middle  of  the  sternum  anteriorly  and  the  middle  of  the  back  posteriorly. 

2.  The  parasternal  line  runs  parallel  to  the  edge  of  the  sternum  and  midway 
between  it  and  the  midcla\-icular  line. 

3.  The  midclavicular  line,  also  called  the  mammary  line,  is  a  longitudinal 


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Fi'j.  211.— The  longitudinal  lines  of  the  chest  used 


cal  diagnosis. 


line  passing  through  the  middle  of  the  clavicle.      This  usually  passes  i  to  2  cm. 
internal  to  the  nipple. 

4.  The  anterior  axillary  line  passes  through  the  anterior  fold  of  the  a.xilla. 

5.  The  midaxillary  line  passes  through  the  middle  of  the  axilla. 

6.  The  posterior  axillary  line  passes  through  the  posterior  fold  of  the  axilla. 

7.  The  scapular  line  passes  longitudinallv  through  thelower  angle  of  the  scapula. 


The    Regions   of   the   Chest. 

In  the  middle  of  the  surface  of  the  chest  anteriorly  there  are  three  regions: 
I.    The  suprasternal  region  is  the  part  above  the  sternum  between  the  sterno- 
mastoid  muscles.      It  is  the  suprasternal  notch. 


THE    CHEST    CONTEXTS. 


193 


2.  The  upper  sternal  region  extends  from  the  suprasternal  notch  to  a  line 
drawn  opposite  the  third  costal  cartilages. 

3.  The  lower  sternal  region  is  behind  the  second  piece  of  the  sternum  from 
the  third  costal  cartilages  down. 

Anteriorly  on  the  chest  there  are  four  regions  (Fig.  212)  ; 

1.  The  supraclavicular  region,  above  the  clavicle.  This  includes  the  supra- 
clavicular fossa. 

2.  The  infraclavicular  region,  below  the  clavicle  down  to  the  upper  edge  of 
the  third  rib. 

3.  The  mammary  region,  from  the  upper  edge  of  the  third  to  the  upper 
margin  of  the  sixth  rib.  This  extends  from  the  edge  of  the  sternum  to  the  anterior 
axillary  fold  and  has  the  nipple  nearly  in  its  centre. 


Fig.  2 1  2. — The  anterior  regions  of  the  chest. 


4.   The  inframammary   region  e.xtends  from  the  upper  margin  of  the  sixth 
rib  to  the  lower  margin  of  the  thorax. 

Laterally  on  the  chest  between  the  folds  of  the  axilla  there  are  two  regions: 

1 .  The  upper  axillary  region  extends  down  to  the  upper  border  of  the  sixth  rib. 

2.  The  lower  axillary  region  extends  from  the  upper  border  of  the  sixth  rib 
to  the  lower  edge  of  the  thorax. 

Posteriorly  there  are  four  scapular  regions  (Fig.   213)  : 

1.  The  suprascapular  region  is  above  the  spine  of  the  scapula. 

2.  The  scapular  region  is  the  part  covered  by  the  bodv  of  the  scapula  below 
its  spine. 

3.  The  infrascapular  region  is  the  part  of  the  chest  below  the  scapula  between 
its  angle  and  the  lower  edge  of  the  chest. 

4.  The  interscapular  region  is  the  part  between  the  posterior  edge  of  the 
scapula  and  the  median  line. 

13 


194 


APPLIED    AXATOMY. 


THE   PLEUR/E. 

The  pleurae  form  dosed  sacs  which  line  the  thorax  (parietal  pleura)  and  cover 
the  surface  of  the  lungs  (visceral  pleura).  As  the  lungs  expand  and  contract,  the 
pleurae  are  only  completely  in  contact  with  the  lungs  when  the  latter  are  fully  dis- 
tended. In  ordinary  breathing  the  lungs  are  not  completely  expanded,  hence  the 
edges  of  the  pleurae  fall  together  and  so  prevent  the  formation  of  a  cavit)'.  This 
collapsing  of  the  pleurae  takes  place  mainly  along  its  anterior  and  lower  edges.  The 
apex  of  the  pleura  is  prevented  from  collapsing  by  its  attachment  to  the  first  rib,  and 
also,  as  pointed  out  by  Sibson,  by  the  attachment  to  it  of  an  expansion  of  the  deejJ- 
cervical  fascia  and  some  fibres  of  the  scalenus  anticus  muscle.  Posteriorly  the  chest 
wall  is  unyielding.  Anteriorly  when  the  lungs  are  collapsed  they  fill  out  the  pleurae 
as   low  down   as   the   fourth    costal   cartilage ;   below  that,    in    front   of   the   heart. 


^li'^,'*.'^ 


INFRA 
^        SCAPULAR 
REGION 

X| 

^11 


a  space  or  sinus  is  left  unoccupied  by  lung.  It  is  called  the  cosforucdiaslinal  simis. 
Likewise  between  the  diaphragm  and  chest-walls  is  another  space,  in  which  the 
parietal  or  costal  and  \dsceral  layers  of  the  pleura  are  in  contact,  called  the  costo- 
phrenic  sinus  or  complcmental  space  of  Gerhardt.  From  these  facts  it  follows  that  the 
outlines  of  the  pleurae  and  lungs  are  identical  posterioriy,  superiorly,  and  antenoriy, 
as  low  as  the  fourth  costal  cartilage.  Here  they  diverge,  the  pleurae  descending 
lower  than  the  lungs. 

The  top  of  the  pleura  is  about  on  a  plane  with  the  upper  surface  of  the  first 
rib.  This  makes  its  posterior  portion  at  the  head  of  the  first  rib  5  cm.  higher 
than  its  anterior  portion  at  the  anterior  end  of  the  first  rib.  The  upper  border 
of  the  cla\-icle  is  le\-el  with  a  point  midway  between  the  anterior  and  posterior 
ends  of  the  first  rib.  This,  therefore,  shows  the  pleura  to  extend  2.5  cm.  (i  in.) 
above  the  level  of  the  upper  surface  of  the  clavicle. 


THE    PLEUR.^. 


195 


The  top  of  the  pleura  does  not  project  into  the  neck  in  the  form  of  a  cone,  but 
resembles  a  drum-head,  being  stretched  in  the  form  of  a  plane  almost  or  quite 
level  with  the  top  of  the  first  rib.  Its  upper  surface  is  strengthened  by  fibres  from 
the  deep  fascias  of  the  neck  and,  according  to  Sibson,  by  some  fibres  from  the 
scalene  muscle. 

The  pleura  then  slopes  forward  behind  the  sternoclavicular  joint  to  meet  the 
pleura  of  the  opposite  side  at  the  level  of  the  second  costal  cartilage,  a  little  to  the  left 
of  the  median  line.  They  then  descend  until  opposite  or  a  little  below  the  fourth 
costal  cartilage,  when  they  each  diverge  toward  the  side,  reaching  the  upper  border 
of  the  seventh  costal  cartilage  near  its  sternal  junction.  They  then  slope  down  and 
out,  reaching  the  lower  border  of  the  se\'enth  rib  in  the  mammary  line,  the  ninth  rib 


Fro.  214. — .Anterior  surface  relations  of  the  lungs  and  pleurse. 

in  the  axillary  line,  and  the  twelfth  rib  posteriorly  (Joessel  and  Waldeyer,  page  51). 
The  scapular  line  intersects  the  lower  edge  of  the  pleura  at  about  the  ele\-enth  rib. 

In  operations  involving  the  lumbar  region,  if  the  incision  is  carried  high  up 
posteriorly  the  pleura  may  be  opened  along  the  lower  border  of  the  posterior 
portion  of  the  twelfth  rib.  It  soon  recedes  from  the  costal  margin  and  in  the 
a.xillary  line  is  about  6  cm.  (2|- in. )  above  it. 

A  heavy  body,  as  a  bullet,  gravitates  to  the  lowest  portion  of  the  pleural  cavity, 
hence  it  can  be  removed  through  an  incision  in  the  eleventh  interspace  posteriorly. 

(Paracentesis  and  enipyema  will  be  alluded  to  after  the  lungs  have  been 
described,  see  p.  200). 


ig6 


APPLIED    ANATOMY. 


THE   LUNGS 

The  lungs  entirely  fill  the  pleural  sacs  when  completely  distended,  but  only 
partly  so  in  quiet,  ordinary  respiration.  They  are  encased  in  a  bony  cage  that  is 
open  below,  on  account  of  which,  when  the  lungs  distend,  they  expand  mostly 
downward.  To  a  less  extent  they  expand,  in  forced  respiration,  both  laterally 
and  anteroposteriorly,  due  to  the  elevation  of  the  ribs  owing  to  the  traction  of  the 
muscles  upon  them.  Ordinary  breathing  is  performed  mainly  by  the  diaphragm. 
It  acts  like  the  piston  of  a  cylinder  and  as  it  descends  the  air  is  drawn  into  the 
trachea  and  lungs.  As  the  diaphragm  falls  a  negative  pressure  is  produced  within 
the  chest  and  were  it  not  for  its  bony  framework,  it  would  collapse.  The  framework 
is  sufficiently  strong  to  retain  its  shape  in  spite  of  this  pressure  if  the  breathing  is 


normal  and  the  chest-walls  are  healthy.  When,  however,  obstruction  of  the  air- 
passages  is  present,  perhaps  from  enlarged  pharyngeal  or  faucial  tonsils  or  nasal 
hypertrophies,  then  the  deformities  known  as  funnel-breast,  pigeon-breast,  etc., 
already  described,  arise.  They  are  also  produced  if  there  is  no  obstruction  to  the 
breathing  but  only  a  weakness  in  the  bony  thorax,  as  occurs  in  rickets. 

Two  of  the  most  common  of  the  diseases  of  the  lungs  produce  changes  in  the 
shape  of  the  thorax ;  they  are  emphysema  and  phthisis.  Pneumonia,  though  a  frequent 
enough  disease,  does  not  produce  any  changes,  as  it  is  too  short  m  its  duration 

in  emphysema  tlie  lungs  are  in  a  state  of  hyperdistention,  hence  they  fill  the 
chest  to  its  greatest  capacitv  and  tend  to  make  the  soft  parts  bulge  between  the  ribs. 
In  phthisis  the  lungs  are  contracted,  hence  the  intrathoracic  pressure  becomes  a 
nec^ative  one  and  the  soft  parts  sink  in  between  their  bony  support.  In  emphysema 
the  anteroposterior  diameter  increases  and  the  chest  assumes  the  barrel-form  already 
described.      In  phthisis  it  becomes  lessened  in  its  anteroposterior  diameter  and  we 


THE    LUNGS. 


197 


have  the  flat  chest.  Enlargement  of  the  chest  posteriorly  is  impossible  on  account  of 
the  support  of  the  ribs,  vertebrje,  and  strong  back  muscles.  Enlargement  downward 
is  allowed  by  a  descent  of  the  diaphragm ;  hence  the  fulness  of  the  abdomen  in  those 
affected  with  emphysema  and  conversely  the  flatness  of  the  abdomen  in  those  having 
phthisis.  In  the  region  of  the  apices  the  thorax  is  closed  by  the  deep  fascia,  which 
spreads  from  the  trachea,  oesophagus,  muscles,  and  great  vessels  and  blends  with  the 
pleura  to  be  attached  to  the  first  rib.  In  the  normal  condition  this  is  level  with  the 
plane  of  the  first  rib  and  rises  little  if  at  all  abo\'e  it.  Even  in  disease  it  is  not 
materially  altered.  This  is  certainly  so  in  phthisis  and  probably  so  in  emphvsema. 
The  apparent  fulness  of  the  supraclavicular  fossae  and  intercostal  spaces  in  emphysema 
and  the  increased  depth  of  these  hollows  in  phthisis  are  not  due  so  much  to  a  bulging 
or  to  a  retraction  of  the  lungs  at  these  points  as  to  the  atrophy  of  the  fattv  and 
muscular  tissue  in  phthisis  and  to  the  muscular  tension  in  emphysema. 

In  coughing,  the  ape.x  of  the  lung  does  not  jump  up  into  the  neck  above  the 
clavicle  as  it  appears  to  do,  but  remains  nearly  or  quite  below  the  plane  of  the  top  of 
the  first  rib.  The  appearance  of  bulging  is  caused  by  the  movements  of  the  trachea 
in  the  median  line  and  the  muscles  laterally.      This  is  noticeable  particularly  in  the 

Sternothyroid  muscle 

Carotid  artery 
'   Sternohyoid  muscle 
/       ,  Subclavian  artery 
\  iHus [ 


Carotid  artery 


bubcla 


First 
Scalenus  anti 


-Upper  end  of  the  tho 


at  the  level  of  the  first  rib. 


case  of  the  platysma  and  omohyoid  muscles.  In  quiet  breathing  the  posterior  belly 
of  the  omohyoid  lies  about  level  with  the  clavicle,  but  in  coughing  it  rises  i  or  2  cm. 
above  it.  The  intercostal  membranes  and  muscles  are  kept  tense  by  the  constant 
elevation  of  the  ribs  due  to  the  muscular  tension. 


OUTLINE  OF  THE  LUNGS. 

Apex. — The  apex  of  the  lung  has  its  highest  point  opposite  the  posterior 
extremity  of  the  first  rib.  It  then  follows  the  plane  of  the  top  of  the  first  rib  down 
to  the  sternoclavicular  joint,  immediately  above  the  junction  of  the  cartilaoe  of  the 
first  rib  with  the  sternum.  The  anterior  end  of  the  first  rib  is  5  cm.  lower  than  the 
posterior.  The  upper  edge  of  the  clavicle  is  2.5  cm.  or  one  inch,  above  the  anterior 
end  of  the  first  rib  and  2.5  cm.  below  the  head  of  the  first  rib,  hence  the  apex  of  the 
lung  rises  2.5  cm.  (i  in.)  above  the  clavicle,  and  it  lies  behind  its  inner  fourth. 
This  distance  will  vary  in  different  indi\iduals  with  the  obliquity  of  the  ribs.  The 
more  oblique  the  ribs  the  greater  will  be  the  distance  between  the  level  of  the  top  of 
the  clavicle  and  that  of  the  neck  of  the  first  rib. 

Anterior  Border. — From  the  sternocla\icular  joint  the  borders  of  the  luno-s 
pass  downward  and  inward  until  they  almost  or  quite  touch  in  the  median  line  at  the 
angle  of  Ludwig  opposite  the  second  costal   cartilage.      They  continue  downward 


igS  APPLIED    ANATOMY. 

almost  in  a  straight  line  until  opposite  the  fourth  costal  cartilage,  where  they  begin  to 
diverge.  The  border  of  the  right  lung  proceeds  downward  and  begins  to  turn  out- 
ward opposite  the  sixth  cartilage. 

The  left  lung  on  reaching  the  level  of  the  fourth  costal  cartilage  curves  outward 
and  downward  across  the  fourth  interspace  to  a  point  about  2.5  cm.  to  the  inner 
side  of  the  nipple  in  the  fourth  interspace.  From  this  point  it  goes  downward  and 
inward  across  the  fifth  rib  and  interspace  to  the  top  of  the  sixth  rib  about  3  cm.  to 
the  inner  side  of  the  nipple  line.  This  isolated  tip  of  lung  just  abo\e  the  sixth  rib 
over  the  apex  beat  of  the  heart  is  called  the  lingula. 

Lower  Border. — The  lower  edge  of  the  lung  varies  in  different  indi^'iduals 
and  in  the  same  individual  according  to  the  amount  of  inflation.  In  quiet  respi- 
ration it  is  about  opposite  the  sixth  cartilage  and  rib  from  the  sternum  to  the  mam- 
mary line,  opposite  the  eighth  in  the  midaxillary  line,  the  tenth  in  the  scapular  line, 
and  the  eleventh  near  the  vertebrce. 

The  Fissures  and  Lobes  of  the  Lungs. — The  left  lung  has  one  fissure  and 
two  lobes,  an  upper  and  a  lower. 

The  right  lung  has  two  fissures  and  three  lobes,  an  upper,  a  micidle,  and  a  lower. 

The  fissure  of  the  left  lung  begins  above  and  posteriorly  opposite  the  root  of  the 
spine  of  the  scapula;  this  is  level  with  the  fourth  rib  and  third  dorsal  spine.  It  passes 
downward  and  forward,  ending  at  the  sixth  rib  in  the  parasternal  line.  It  crosses  the 
fourth  in  the  midaxillary  line.  The  lower  lobe  of  the  right  lung  is  of  the  same  size 
as  that  of  the  left  side.  The  lung  above  it  is  divided  into  a  middle  and  upper  lobe. 
The  main  fissure  of  the  right  lung  corresponds  in  its  course  almost  exactly  with  that 
of  the  left  lung.  It  begins  abo\'e  and  posteriorly  at  the  root  of  the  spine  of  the 
scapula  and  passing  downward  crosses  the  fourth  rib  in  the  midaxillary  line  and  ends  at 
the  sixth  rib  in  the  mammary  line  (instead  of  the  parasternal  line  as  in  the  left). 

The  subsidiary  fissure  of  the  right  lung  leaves  the  main  fissure  at  the  posterior 
axillary  line  opposite  the  fourth  rib  and  follows  this  rib  in  an  almost  horizontal  direc- 
tion to  its  junction  with  the  sternum. 

In  order  to  recognize  and  appreciate  the  changes  which  occur  in  the  lungs  in 
lobar  pneumonia  it  is  necessary  to  know  the  outlines  and  limits  of  the  various  lobes  of 
the  lungs.  :A  knowledge  of  the  exact  course  of  the  fissures  of  the  lungs  is  not  only 
necessary  to  outHne  the  lobes,  but  it  is  of  service  in  the  diagnosis  of  pleural  effusions. 
These  effusions  often  are  limited  to  certain  localized  areas  instead  of  being  general. 

Pleurisy  may  affect  the  lung  bordering  the  fissures.  When  such  is  the  case,  the 
eft'usion,  serous  or  purulent,  may  be  in  the  fissure  itself  and  embrace  but  little  of  the  gen- 
eral pleural  cavity.  Dry  taps  from  failure  to  hit  the  purulent  or  serous  collection  are 
not  infrequent,  and  the  possibility  of  its  being  interlobular  should  be  borne  in  mind. 

GENERAL    CONSIDERATIONS. 

From  what  has  been  said  it  follows  that  a  knowledge  of  the  extent  and  outlines 
of  the  lungs  and  of  the  location  and  course  of  the  fissures  is  essential  to  the  proper 
diagnosis  and  treatment  of  affections  of  both  the  lungs  and  pleurae. 

The  extent  of  the  lungs  is  determined  in  the  living  by  percussion.  The  apex  of 
the  lungs  forms  an  oblique  plane  running  upward  and  backward  from  just  below  the 
lower  edge  of  the  inner  extremity  of  the  clavicle  to  the  neck  of  the  first  rib  above 
and  posteriorly.  The  level  of  these  two  points  will  vary  according  to  the  inclination 
of  the  ribs,  which  in  turn  is  influenced  by  the  direction  (\'ertican  of  the  spine.  Ordi- 
narily the  distance  is  5  cm.  (2  in.).  It  may  be  e\-en  as  much  as  7  or  8  cm.  The 
top  edge  of  the  clavicle  passes  across  the  middle  of  this  distance  so  that  the  top  of 
the  lung  is  about  2.5  cm.  {  i  in.)  above  the  clavicle.  The  highest  point  of  the  lung 
is  not  in  the  middle  of  the  space  enclosed  by  the  first  rib,  but  is  at  its  posterior 
border,  at  the  neck  of  the  first  rib. 

In  percussing,  one  should  not  strike  directly  backward  but  both  downA\-ard  and 
backward. 

If  the  patient  is  standing  erect  the  first  rib  will  slope  downward  and  forward  at  an 
angle  of  65  degrees,  or  more,  with  a  ^■ertical  line.  The  spine  will  slope  downward  and 
backward  from  the  same  vertical  line  in  a  normally  straight  back  about  20  degrees. 


THE   LUNGS.  199 

In  people  with  straight  backs  and  flat  chests  (often  seen  in  phthisis),  the  sloping 
downward  of  the  ribs  is  marked;  in  those  with  rounded  backs  the  chest  is  apt  to  be 
round,  as  in  emphysema,  and  then  the  ribs  are  more  horizontal. 

Another  point  to  be  noticed  is  the  lateral  extent  of  the  ape.x  of  the  lung  in 
relation  to  the  length  of  the  clavicle.  The  lung  does  not  extend  farther  out  on  the 
clavicle  than  one-fourth  its  length.  The  cla\-icular  origin  of  the  sternomastoid 
muscle  extends  out  one-third  of  the  length  of  the  clavicle,  so  that  the  lung  is  behind 
the  clavicular  origin  of  the  sternomastoid  and  care  should  be  taken  not  to  percuss 
too  far  out.  If  the  finger  is  laid  in  the  supraclavicular  fossa  in  percussion  it  should 
be  pressed  downward  and  inward,  not  backward. 

Posteriorly  the  scapula  rises  to  the  second  rib  and  its  spine  has  its  root  opposite 
the  fourth  rib  or  spinous  process  of  the  third  thoracic  vertebra.  Therefore  a  small 
portion  of  the  lung  is  above  the  upper  edge  of  the  scapula  and  percussion  in  the 
supraspinous  fossa  gives  a  clear  resonant  note. 

Behirid  the  middle  of  the  first  piece  of  the  sternum  passes  the  trachea,  crossed 
by  the  left  innominate  vein.      The  trachea  of  course  contains  air;  the  lungs  slope 


Fig.  217. — Formalin-hardened  bod>-.  showing  the  right  lung  collapsed  and  compressed  by  a  large 
pleural  ettusion. 

inward  from  the  sternocla\'icular  joints  to  meet  nearly  or  quite  in  the  median  line 
and  so  continue  to  the  level  of  the  fourth  rib;  hence  it  follows  that  the  percussion 
note  on  the  sternum  nearly  down  to  this  point  is  resonant  and  if  it  be  found  to  be 
dull  one  should  look  for  an  aneurismal  or  other  tumor  which  is  displacing  or 
covering  the  lungs  and  trachea  at  this  point  and  thereby  subduing  their  resonance. 
^  Below  the  fourth  rib  the  area  of  the  absolute  heart  dulness  becomes  evident. 
(This  will  be  alluded  to  in  describing  that  organ  later  on. ) 

In  performing  abdominal  operations,  as  those  involving  the  gall-bladder  and 
kidney,  the  surgeon  may  be  tempted  to  prolong  his  incision  upward  into  the  lower 
edge  of  the  chest-walls,  and  it  is  necessary  to  know  how^  far  he  can  proceed  without 
opening  the  pleural  cavity.  This  necessitates  his  knowing  how  far  from  the  lower 
edge  of  the  chest  the  pleura  lies.  It  reaches  to  the  seventh  rib  in  the  mammary  line, 
the  ninth  in  the  axillary  line,  and  the  twelfth  posteriorly,  extending  to  its  extreme 
lower  edge. 

In  the  axillary  line  the  pleura  is  about  6  cm.  (2|  in.)  away  from  the  edge  of 
the  thorax.  This  distance  gets  less  as  one  proceeds  forward  to  the  sternum  and 
backward  toward  the  spine. 


200  APPLIED    ANATOMY. 

In  emphysema  the  lung,  being  distended,  occupies  more  nearly  the  outlines  of  the 
pleura  and  its  area  of  resonance  is  increased.  I  n  pleural  effusion  it  is  compressed  and  even 
sometimes  collapsed.  As  it  shrinks  it  recedes  inward  and  backward  and  is  pushed 
from  the  chest-wall  by  the  layer  of  fluid  (Fig.  217J.  The  pressure  of  the  fluid  within 
causes  the  intercostal  spaces  to  be  obliterated  and  sometimes  even  to  bulge  instead  of 
being  depressed.  As  the  expansion  of  the  lung  is  prevented,  the  chest  does  not  move 
on  the  affected  side,  or  expand  with  the  respiration,  as  it  does  on  the  healthy  side. 
This  can  be  demonstrated  by  measuring  the  two  sides  of  the  chest.  At  the  end 
of  expiration  the  affected  side  will  be  from  i  to  3  cm.  greater  in  circumference  than  the 
healthy  one.  If  the  pleural  effusion  is  on  the  right  side  it  may  push  the  heart  to  the 
left  and  raise  its  apex  beat  and  cause  it  to  pulsate  beyond  the  nipple  line  and  even  in 
the  axilla.  If  it  is  on  the  left  side  the  costomediastinal  sinus  (page  196)  becomes 
distended  with  fluid  or  plastic  lymph  and  this  obscures  or  conceals  the  heart's  impulse. 
If  the  effusion  is  very  large  the  heart  is  pushed  over  toward  the  right  and  its  apex 
beat  is  seen  in  the  third  or  fourth  interspace  on  the  right  side  even  so  far  over  as 
the  mammary  line. 

Should  the  eft'usion  be  purulent  it  may  perforate  the  chest-wall,  or  open  into  the 
pericardium  anteriorly,  the  cesophagus  posteriorly,  and  into  the  stomach  or  peritoneal 
cavity  below.  If  it  perforates  the  chest-wall  it  usually  does  so  anteriorly  between  the 
third  and  sixth  interspaces,  most  often  in  the  fifth. 

Paracentesis. — Where  the  pleural  effusion  is  serous  it  is  usually  drawn  oft'  by 
an  aspirating  needle  or  trocar. 

For  diagnostic  purposes  a  hypodermic  syringe  needle  is  often  used,  as  the  chest- 
walls  are  usually  thin  enough  to  allow  this  to  be  done,  particularly  if  a  suitable  spot 
is  chosen  and  the  patient  is  a  child.  Care  should  be  exercised  not  to  strike  a  rib. 
The  spot  chosen  for  puncture  may  be  indicated  by  dulness  on  percussion.  It  may 
be  anywhere,  but  when  a  choice  is  permissible  the  puncture  should  be  made  in  the 
sixth  interspace  about  in  the  middle  or  postaxillary  line.  Another  preferred  spot  is 
in  the  eighth  interspace,  below  the  angle  of  the  scapula.  The  sixth  interspace  may  be 
determined  in  several  ways,  viz. : 

1.  Begin  at  the  angulus  sterni  (angle  of  Ludwig)  and  follow  out  the  second  rib 
to  the  parasternal  or  midclavicular  line,  thence  count  down  to  the  sixth  rib  and 
follow  it  to  the  midaxillary  line. 

2.  The  nipple  is  in  the  fourth  interspace,  follow  it  to  the  axillary  line  and  count 
two  spaces  down. 

3.  The  apex  beat  of  the  heart  is  in  the  fifth  interspace,  follow  it  around  to  the 
axillary  line  and  take  the  next  space  below. 

4.  Find  the  last  rib  that  articulates  with  the  sternum — it  is  the  seventh ;  follow  it 
around  and  take  the  space  above. 

5.  With  the  arm  to  the  side  the  inferior  angle  of  the  scapula  marks  the  seventh 
interspace;  take  the  interspace  next  abo\e. 

6.  A  horizontal  line  at  the  level  of  the  nipple  cuts  the  midaxillary  line  in  aliciut 
the  sixth  interspace. 

7.  The  lower  edge  of  the  pectoralis  major  touches  the  side  of  the  chest  at  the 
fifth  rib.      Follow  it  to  the  axillary  line  and  go  two  spaces  lower. 

8.  By  raising  the  arm  the  serrations  of  the  serratus  anterior  muscle  attached  to 
the  fifth,  si.xth,  seventh,  and  eighth  ribs  become  visible;  that  attached  to  the  sixth  rib 
is  the  most  prominent  and  is  attached  farthest  forward. 

Empyema. — When  the  pleural  effusion  is  purulent,  tapping  is  not  sufficient, 
and  drainage  is  resorted  to.  It  is  not  considered  necessary  to  open  the  pleural 
cavity  at  its  lowest  part  but  the  sites  chosen  are  usually  the  sixth  or  seventh  inter- 
space in  the  mid-  or  postaxillary  line.  The  movements  of  the  scapula  are  apt  to 
interfere  with  drainage  immediately  below  its  angle,  hence  the  opening  is  usually 
made  farther  forward.      The  surgeon  may  or  may  not  resect  a  rib. 

The  ribs  may  lie  so  close  together  as  to  compress  the  drainage-tube;  in  such 
case  a  resection  is  done  if  the  patient's  condition  permits. 

Incision  for  Empyenia. —  In  certain  cases  the  condition  of  the  patient  may 
demand  that  as  little  as  possible  be  done,  and  that  quickly.  The  point  of  operation 
is  selected  by  one  of  the  guides  already  given,  perhaps  the  level  of  the  nipple. 


THE    PERICARDIUM.  201 

While  the  finger  of  one  hand  marks  the  interspace,  an  incision  4  cm.  (i '2  in.) 
long  is  made  along  the  upper  edge  of  the  rib,  this  is  deepened  by  a  couple  of 
strokes  which  detach  the  intercostal  muscles  and  carefully  penetrate  the  pleura. 
As  the  pus  makes  its  appearance  the  knife  is  vvithdrawn  and  the  finger  is  laid  on 
the  opening.  A  drainage-tube  held  in  a  curved  forceps  is  then  slid  along  the  finger 
into  the  chest.  Sometimes  a  rubber  tracheotomy  tube  is  used  for  drainage  purposes. 
Any  bleeding  will  be  from  the  small  intercostal  branches  and  can  readily  be  stopped 
by  gauze  packing. 

The  incision  is  made  along  the  upper  edge  of  the  rib  because  the  intercostal 
artery  running  along  the  lower  edge  of  the  rib  is  the  larger. 

Resection  of  a  Rib  for  Empyema. — For  the  removal  of  a  part  of  a  rib  a  more 
formal  operation  is  necessary.  The  incision  is  made  directly  on  the  rib  down  to 
the  bone  and  five  or  more  centimetres  in  length.  The  skin  being  retracted,  the 
periosteum  is  incised  and  detached  from  the  rib  with  a  periosteal  elevator  which  is 
passed  down  its  posterior  surface,  pushing  the  pleura  away  from  the  rib.  When 
the  elevator  reaches  the  lower  border  of  the  rib  an  incision  is  made  down  on  it 
through  the  intercostal  muscles,  keeping  as  close  to  the  rib  as  possible  to  avoid 
wounding  the  intercostal  artery,  which  lies  close  to  its  lower  edge.  The  rib  is 
then  divided  either  with  a  cutting  forceps  like  Estlander's,  or  a  GigH  saw.  The 
rib,  having  been  divided  at  one  end  of  the  incision,  is  then  lifted  up,  the  pleura 
stripped  off,  and  divided  at  the  opposite  end. 

Should  the  intercostal  artery  bleed,  and  it  is  often  sufficiently  large  to  spurt 
quite  actively,  it  can  be  caught  with  a  hjemostatic  forceps  and  secured  with  a 
ligature  if  necessary.  This  is  safer  than  to  trust  to  packing,  on  account  of  the 
lack  of  support  due  to  the  removal  of  the  rib.  After  the  incision  is  completed, 
the  pleura  is  incised  and  the  tube  introduced.  In  ligating  the  intercostal  artery, 
care  should  be  taken  not  to  include  the  nerve  which  lies  close  to  but  below  it;  that 
is,  farther  away  from  the  rib. 

THE   PERICARDIUM. 

The  pericardium  is  composed  of  fibrous  tissue  lined  with  a  serous  membrane. 

When  affected  by  inflammation  the  amount  of  fluid  contained  in  it  becomes 
increased  and  it  becomes  distended  and  may  interfere  with  the  functions  of  the  heart 
and  adjacent  structures. 

If  the  effusion  is  serous  it  is  sometimes  drawn  off  by  puncture;  if  it  is  purulent 
drainage  is  instituted. 

The  pericardium  in  shape  is  somewhat  conical.  Its  base  rests  on  the  central 
tendon  of  the  diaphragm  and  its  apex  envelops  the  great  vessels,  as  they  emerge 
from  the  base  of  the  heart,  for  a  distance  of  4  to  5  cm.  The  attachment  to  the 
diaphragm  is  most  firm  at  the  opening  of  the  inferior  vena  cava.  As  the  fibrous 
layer  of  the  pericardium  proceeds  upward  it  becomes  lost  in  the  fibrous  tissue 
(sheath)  covering  the  great  vessels.  This  is  continuous  above  with  the  deep  cervical 
fascia,  especially  with  its  pretracheal  layer.  Anteriorly  the  pericardium  is  attached 
above  and  below  to  the  sternum  by  the  so-caWed  stej'nopericardiac  iigamefits  (Fig.  218). 

In  front  of  it  above  are  the  remains  of  the  thymus  gland  and  triangularis  sterni 
muscle  of  the  left  side  from  the  third  to  the  seventh  costal  cartilages.  The  internal 
mammary  arteries,  running  down  behind  the  costal  cartilages  about  a  centimetre 
from  the  edge  of  the  sternum  above  and  somewhat  more  below,  are  separated  from 
the  pericardium  by  the  edges  of  the  lungs  and  pleurse,  these  latter  reaching  nearly  or 
quite  to  the  median  line.  The  triangularis  sterni  muscle  also  lies  beneath  the  artery 
and  farther  from  the  surface.  As  the  left  pleura  slopes  more  rapidly  toward  the  side 
than  does  the  right  there  is  a  small  portion  of  the  pericardium  uncovered  by  the  pleura 
at  about  the  sixth  intercostal  space  close  to  the  sternum.  The  incisura  of  the  left 
lung  leaves  a  space  where  the  pericardium  is  separated  from  the  chest-walls  onlv  by 
the  pleura. 

On  each  side  the  pleura  and  pericardium  are  in  contact,  with  the  phrenic  ner\es 
between  them.  Posteriorly  the  pericardium  lies  on  the  bronchi,  the  oesophagus,  and 
the  thoracic  aorta. 


202  APPLIED    ANATOMY. 

Owing  to  the  fibrous  nature  of  the  pericardium  it  will  not  expand  suddenly. 
While  only  about  a  pint  of  liquid  can  be  injected  into  the  normal  pericardial  ca\'ity 
after  death,  if  a  chronic  effusion  exists  in  a  living  person  as  much  as  three  pints  may 
be  present. 

Sudden  effusion  occurring  in  the  living  patient  will  cause  obstruction  of  the  cir- 
culation at  the  base  of  the  heart;  it  may  by  pressure  on  the  bronchi  at  the  bifurcation 
produce  suffocative  symptoms  and  by  pressure  on  the  cesophagus  difficulty  in  swallow- 
ing. The  lungs  are  displaced  laterally,  and  the  stomach  and  liver  downward.  The 
largest  effusions  are  slow  in  their  formation. 

Pressure  on  the  left  recurrent  laryngeal  nerve  as  it  winds  around  the  aorta 
sometimes  produces  alteration  or  loss  of  the  voice. 

In  children,  according  to  Osier,  the  praecordia  bulges  and  the  anterolateral  region 
of  the  left  chest  becomes  enlarged  as  does  also  the  area  of  the  cardiac  dulness. 

Paracentesis  of  the  Pericardium. — Tapping  the  pericardium  by  means  of  a 
trocar  or  aspirating  needle  must  be  carefully  done,  or  the  pleura  may  be  punctured. 


Fig.  2iS. — View  of  the  pericardium,  slightly  distended,  and  its  relations  to  the  bony  thorax. 

The  part  of  the  pericardium  in  contact  with  the  chest-wall  and  not  covered  by 
pleura  is  very  small.  It  embraces  the  space  between  the  two  pleuree  from  the  fourth 
to  the  seventh  ribs.  This  may  be  defined  by  three  lines,  one  in  the  midline,  another 
from  the  middle  of  the  sternum  opposite  the  fourth  rib  to  the  costosternal  junction 
of  the  seventh  rib,  and  a  third  joining  these  two  passing  through  the  articulation  of 
the  xiphoid  cartilage  (Fig. 219). 

The  left  pleural  sac  may  be  i  cm.  farther  from  the  edge  of  the  sternum  than  the 
right.  Thus  it  is  seen  that  there  is  hardly  a  point  where  a  needle  can  be  introduced 
with  the  certainty  of  avoiding-  the  pleura.  The  safest  point  is  probably  close  to  the 
left  edge  of  the  sternum  in  the  sixth  interspace.  This  interspace  may  not  extend 
to  the  sternum,  but  even  if  the  cartilages  are  in  contact  a  needle  could  probably  be 
introduced  at  this  point.  As  the  pericardium  is  distended  it  carries  the  lungs  and  to 
a  less  extent  the  pleura  outwards  and  increases  the  area  a\ailable  for  puncture  both 


THE    PERICARDIUM, 


203 


upward  and  downward  as  well  as  to  the  sides;  When  greatly  distended  the  peri- 
cardium may  reach  to  the  first  interspace  above,  2.5  cm.  (  i  in.)  to  the  right  of  the 
sternum,  to  the  seventh  cartilage  below,  and  to  the  left  nipple  line  or  even  beyond. 
The  arching  of  the  diaphragm  causes  a  sternophrenic  sinus  behind  the  sternum  anal- 
ogous to  the  costophrenic  sinus  at  the  lower  edge  of  the  chest.  This  becomes  dis- 
tended by  pericardial  effusions  in  the  same  manner  as  does  the  costophrenic  sinus  in 
pleural  effusions.  A  puncture  in  the  si.xth  space  close  to  the  left  edge  of  the  sternum 
enters  this  sinus.  The  increased  area  in  cases  of  distention  from  pericardial  effusions 
has  led  Osier  to  advise  tapping  in  the  fourth  interspace,  either  at  the  left  sternal 
margin  or  2.5  cm.  from  it,  or  at  the  fifth  interspace  4  cm.  (i  ^  in.)  from  the  sternal 
margin:  or  by  thrusting  the  needle  upward  and  backward  close  to  the  costal  margin 
in  the  left  costo.xiphoid  angle. 

It  is  important  to  avoid  wounding  the  internal  mammary  artery,  which  is  usually 


ntesis  of  the  pjericardii 


nearer  to  the  sternum  above  (^0.5  to  i  cm.  to  its  outer  side)  and  farther  from  it  (_2  to 
3  cm.  )  below. 

The  danger  of  wounding  the  pleura  in  aspirating  with  a  needle  has  probably 
been  overestimated,  but  when  drainage  is  to  be  employed  the  danger  is  certain. 

Drainage  of  the  Pericardium. — To  drain  the  pericardium  requires  the 
removal  usually  of  at  least  one  of  the  costal  cartilages.  A  drainage-tube  can  some- 
times be  introduced  by  first  making  a  short  incision  in  the  fifth  or  si.xth  interspace 
close  to  the  left  edge  of  the  sternum,  then  puncturing  the  pericardium,  dilating  the 
puncture  with  forceps,  and  introducing  the  tube.  The  costal  cartilages  usually  he  so 
close  together  as  to  interfere  with  the  proper  introduction  of  a  tube,  hence  the  neces- 
sity of  resection.  A  flap  may  be  made  or  a  straight  incision.  The  latter  is  some- 
times made  o\er  the  fifth  costal  cartilage,  which  is  then  resected.  If  desired  the 
si.xth  and  se\-enth  cartilages  are  also  removed  and  even  a  piece  of  the  left  edge  of  the 
sternum.      The  intercostal  muscles  ha\-ing  been  raised,  the'  cartilages  are  removed. 


204  APPLIED    ANATOMY. 

When  the  internal  mammary  artery  is  seen  lying  beneath,  it  is  to  be  either  ligated 
or  drawn  to  one  side.  The  triangularis  sterni  muscle  is  either  incised  or  drawn  to 
the  outer  side  along  with  the  edge  of  the  left  pleura.  The  pericardium  can  then  be 
lifted  with  forceps  and  incised  and  the  drainage-tube  introduced. 

THE  HEART. 

In  size  the  heart  is  somewhat  larger  than  the  clenched  fist.  It  measures  12,5 
cm.  (5  in.)  in  length,  7.75  cm.  (3j^  in.)  in  width,  and  6.25  cm.  (2j4  in.)  in  thick- 
ness. Its  weight  in  the  adult  male  is  250  to  300  Gm.  (8  to  10  oz.  ),  in  the  female 
it  is  60  Gm.  (2  oz.)  less. 

It  lies  enclosed  in  its  pericardium  in  the  middle  mediastinum  between  the 
sternum  (from  the  upper  edge  of  the  third  costal  cartilage  to  the  sternoxiphoid  artic- 
ulation) in  front,  and  the  bodies  of  the  fifth,  si.xth,  seventh,  and  eighth  thoracic  ver- 
tebrae behind.  Laterally  it  reaches  from  two  centimetres  to  the  right  of  the  sternum 
nearly  to  the  left  nipple  line.  On  each  side  of  it  are  the  lungs,  from  which  it  is 
separated  by  the  pleurse  and  pericardium  with  the  phrenic  nerves  between.  Above 
are  the  great  vessels  and  below  it  rests  on  the  central  tendon  of  the  diaphragm. 

In  shape  the  heart  resembles  an  acorn,  the  atria  (auricles),  forming  the  upper 
right  portion  and  the  ventricles  the  lower  left  portion.  It  lies  with  its  right  side 
resting  on  the  diaphragm  and  its  apex  pointing  forward  and  to  the  left. 

For  con\'enience  one  speaks  of  a  base,  an  apex,  a  right  border,  a  lower  border, 
and  a  left  border. 

OUTLINES   OF  THE   HEART. 

The  base  of  the  heart  is  opposite  the  upper  border  of  the  third  costal  cartilage. 
It  is  here  that  the  superior  vena  cava  ends  and  the  aorta  begins.  It  extends  from 
1.25  cm.  (^2  in.)  to  the  right  of  the  sternum  to  2.5  cm.  (i  in.)  to  the  left  of  the 
sternum. 

The  right  border  of  the  heart  extends  from  1.25  cm.  (\i  in.)  to  the  right  of  the 
sternum  at  the  upper  border  of  the  third  costal  cartilage  in  an  outwardly  cur^'ed  line 
to  the  junction  of  the  seventh  rib  and  the  sternum.  In  the  fourth  interspace  it  ma}^ 
reach  2.5  cm.  ( i  in.)  beyond  the  right  edge  of  the  sternum. 

The  lower  border  passes  from  the  seventh  right  chondrosternal  junction  across 
the  sternoxiphoid  joint  outward  in  the  fifth  interspace  to  the  apex  beat,  which  is  4 
to  5  cm.  ( I  yi  in.  to  i  S/j^  in. )  below  and  to  the  inner  side  of  the  nipple  and  about 
8.75  cm.  (33^2  in.)  to  the  left  of  the  median  line.  This  marks  the  extreme  left  limit 
of  the  heart.  In  children  the  ape.x  is  higher — it  is  in  the  fourth  interspace.  In  old 
people  it  is  lower. 

The  left  border  arches  upward  from  the  ape.x  beat,  as  just  gi\'en,  in  an  inward 
and  upward  direction  to  2.5  cm.  ( i  in.)  to  the  left  of  the  sternum  at  the  upper  border 
of  the  third  costal  cartilage. 

The  atrio-  (auriculo-)  \'entricular  groove  or  line  of  junction  between  the  atria 
(auricles)  and  ventricles  runs  from  the  sixth  right  chondrosternal  junction  upward 
and  to  the  left  to  the  third  left  chondrosternal  junction.  The  atria  lie  above  and  to 
the  right  of  this  line  and  the  ventricles  below  and  to  the  left. 

The  right  atrium  (auricle)  and  right  ventricle  lie  anteriorly  and  the  left  atrium 
and  left  ventricle  lie  posteriorly.  In  the  right  atrioventricular  groove  runs  the  right 
coronary  artery.  As  it  lies  on  the  anterior  portion  of  the  heart  it  is  liable  to  be  injured 
in  stab-Avounds  and  give  rise  to  fatal  bleeding,  as  may  also  the  interventricular 
branch  of  the  left  coronary  artery  as  it  passes  down  near  the  left  border  of  the  heait 
between  the  right  and  left  ventricles. 

The  Portion  of  the  Heart  Uncovered  by  Lung-tissjie. — When  the  lungs  are 
distended  the  right  lung  covers  the  heart  to  the  median  line.  The  left  lung  lea\es 
the  median  line  at  the  level  of  the  fourth  costal  cartilage  and  cur\'es  outward  and 
downward  to  about  the  ape.x  beat  in  the  fifth  interspace,  2.5  cm.  to  the  inner  side  of 
the  nipple  line.  At  this  point  a  small  piece  of  the  lung,  the  lingula,  sometimes 
curves  around  in  front  of  and  below  the  extreme  tip  of  the  heart.  As  the  air  leaA-es 
the  lungs  they  retract  and  their  anterior  borders  hardly  reach  the  edges  of  the  sternum. 


THE    HEART. 


205 


Area  of  Cardiac  Dulness. — The  area  of  cardiac  dulness  corresponds  to  the 
area  uncovered  by  huig  and  in  contact  with  the  chest-wall.  This  is  the  area  of  abso- 
lute dulness.  It  begins  opposite  the  fourth  costal  cartilage  and  extends  down  the 
sternum,  between  the  median  line  and  left  edge,  to  the  liver  dulness  below  opposite 
the  sixth  costal  cartilage.  Toward  the  left  side  it  arches  from  the  fourth  left  costo- 
sternal  junction  to  the  apex  beat.  The  area  of  so-called  relative  dulness  caused  by 
overlapping  of  the  lungs  extends  along  the  right  edge  of  the  sternum  to  opposite  the 
upper  border  of  the  third  rib  above,  and  to  the  left  follows  parallel  to  the  left  border  of 
the  heart  to  the  tip  of  its  apex.     Below  it  blends  with  the  li\'er  dulness  (Fig.  221). 

The  area  of  cardiac  dulness  may  be  increased  not  only  by  the  enlargement  of  the 
heart  itself  but  by  pericardial  effusions  and  disease  such  as  aneurism  of  the  great  vessels. 

In  an  early  stage  of  pericardial  effusion  and  also  in  aneurism  there  may  be  an 


Fig.  220. — Relations  of  the  heart,  its  valves,  and  the  great  blood-vessels  to  the  surface  of  the  chest. 

extension  of  the  area  of  dulness  upward.      In  a  later  stage  of  pericarditis  the  lateral 
area  of  dulness  becomes  increased. 

Cardiohepatic  Angle  (Ebstein).  —  This  is  the  angle  formed  by  the  right 
border  of  the  heart  as  it  meets  the  liver.  It  is  a  more  or  less  resonant  area  in  the 
fifth  right  intercostal  space.  Below  it  is  the  liver  dulness  and  above  and  towards 
the  median  line  is  the  heart. 


VALVES   OF  THE    HEART. 

There  are  two  types  of  valves  in  the  heart:  the  bicuspid  [mitral)  and  trimspid 
between  the  atria  (auricles)  and  ventricles,  and  the  two  sets  of  semilunar  valves  at 
the  entrance  of  the  pulmonary  artery  and  aorta.      (  See  Fig.  220.  ) 

The  bicuspid  valve  is  the  most  important  and  is  the  deepest  seated.  It  lies 
at  the  edge  of  the  left  border  of  the  sternum  opposite  the  fourth  costal  cartilage. 
It  separates  the  left  atrium  and  ventricle  and  lies  nearly  transversely. 


2o6  APPLIED    ANATOMY. 

The  tricuspid  valve  lies  in  the  middle  of  the  sternum  opposite  the  fourth 
intercostal  space.  It  runs  obliquely  downward  and  to  the  right  from  the  third  left 
intercostal  space  to  the  fifth  right  costal  cartilage.  It  separates  the  right  atrium  and 
ventricle. 

The  pulmonary  semilunar  valve  lies  opposite  the  sternal  end  of  the  third  left 
costal  cartilage.  It  is  the  most  superficial  \^al\-e  and  the  one  highest  up  on  the  ster- 
num.     It  prevents  regurgitation  of  the  blood  into  the  right  ventricle  from  the  lungs. 

The  aortic  semilunar  valve  lies  under  the  left  side  of  the  sternum  about  level 
with  the  lower  edge  of  the  third  costal  cartilage.  It  is  just  below  and  to  the  right  of 
the  pulmonary  valve,  and  above  and  to  the  left  of  the  bicuspid  valve. 

Location   of   Vala"ular    Sounds. 

The  sounds  produced  by  the  closure  of  the  \alves  do  not  correspond  with  the 
position  of  the  valves,  but  are  as  follows. 

The  bicuspid  sound  is  heard  most  distinctly  at  the  apex  of  the  heart  as  far 
inward  as  the  parasternal  line  and  as  high  as  the  third  interspace.  It  is  transmitted 
around  the  chest  toward  the  a.xilla. 

The  tricuspid  sound  is  best  heard  at  the  left  sternal  border  between  the  fifth 
and  sixth  costal  cartilages  (Tyson  ). 

The  pulmonary  sound  is  best  heard  in  the  second  interspace  to  the  left  of  the 
sternum;  the  cartilage  above  is  called  the  pulmonary  cartilage. 

The  aortic  sound  is  best  heard  in  the  second  right  intercostal  space  and  the 
cartilage  abo\-e  is  called  the  aortic  cartilage.  The  aortic  sounds  are  transmitted  up 
the  neck  in  the  direction  of  the  great  blood-vessels. 

VARIATION  IN  SIZE  AND  POSITION  OF  THE  HEART. 

The  heart  becomes  enlarged  both  by  being  dilated  and  by  being  h^-pertrophied, 
usually  both  conditions  are  present;  and  its  position  is  often  changed  by  disease  both 
of  itself  and  of  adjacent  organs.  It  is  apt  to  enlarge  unequally.  In  emphysema  and 
bicuspid  regurgitation  the  right  side  becomes  enlarged,  the  pulmonary  circulation 
being  impeded.  In  aortic  disease,  arteriosclerosis,  muscular  exertion,  or  any  cause 
impeding  the  course  of  the  blood  through  the  arteries  there  is  produced  an  enlarge- 
ment of  the  left  side  of  the  heart. 

The  average  weight  of  the  healthy  heart  is  in  the  male  2S0  Gm.  (9  oz. ),  and  in 
the  female  250  Gm.  (8  oz. ).  These  may  be  doubled  in  cases  of  enlargement. 
When  the  heart  is  enlarged  the  apex  beat  changes  its  position;  it  may  occupy  the 
sixth,  seventh,  or  eighth  interspace  instead  of  the  fifth,  and  may  be  as  far  as  5  to  7.5 
cm.  (2  to  3  in.)  to  the  left  of  the  nipple  line. 

When  it  enlarges  upward,  instead  of  the  absolute  dulness  beginning  opposite  the 
fourth  costal  cartilage,  it  is  opposite  the  third  or  e\-en  the  second  interspace.  Tov.-ard 
the  right  side  the  absolute  clulness  may  extend  a  cou]3le  of  centimetres  beyond  the 
right  edge  of  the  sternum,  instead  of  being  near  its  left  edge  as  is  normal. 

The  heart  is  readily  displaced  by  pressure  from  the  surrounding  structures.  If 
there  is  abdominal  distention  by  gas  or  ascites,  or  if-  the  li\'er  or  spleen  is  enlargetl, 
the  heart  is  pushed  upward.  Enlargement  of  the  liver  ma)^  likewise  depress  the 
heart,  if  the  patient  is  in  an  upright  position,  by  the  weight  of  the  li\'er  dragging  it 
down.  Aneurisms  of  the  arch  of  the  aorta,  tumors,  or  emphysema  may  also  depress 
it.      In  the  aged  the  apex  beat  may  be  normally  in  the  sixth  interspace. 

Lateral  displacement  occurs  in  cases  of  pleural  effusion.  Osier  says  (' '  Pract.  of 
Med.,"  p.  594),  this  is  not  due  to  a  twisting  of  the  heart  on  its  axis  but  to  a  positive 
lateral  dislocation  of  the  heart  and  pericardium.  Pneumothora.x  or  tumors  on  one  side 
may  also  push  the  heart  toward  the  opposite  side.  It  may  be  pulled  to  one  side  by 
pleural  adhesio.ns  and  in  those  cases  of  fibroid  phthisis  in  which  the  lung  becomes 
markedly  retracted.     Abscess  or  tumors  of  the  mediastinum  also  displace  it. 

The  position  of  the  pulsation  of  the  heart  is  not  always  an  indication  of  the  posi- 
tion of  the  apex.  In  pleural  effusion  the  pulsation  may  be  one,  two,  or  three  inter- 
spaces higher  than  normal,  while  the  ape.x  itself  may  not  be  elevated. 


THE   HEART.  207 


WOUNDS   OF  THE   HEART. 

Wounds  of  the  heart  are  usually  immediately  fatal,  but  sometimes  they  are  not 
so.  The  pleurae  are  very  liable  to  be  wounded  at  the  same  time.  The  right  ven- 
tricle, on  account  of  lying  anteriorly,  is  the  part  most  often  involved.  The  atria  lie 
more  posteriorly  and  are  most  apt  to  be  wounded  in  stabs  through  the  back.  Not 
only  may  the  substance  of  the  heart  itself  be  injured  but  also  its  blood-vessels.  The 
right  coronary  artery  lying  in  the  atrioventricular  groove  and  the  anterior  interven- 
tricular branch  of  the  left  coronary  running  between  the  two  ventricles  anteriorly  are 
the  A-essels  most  liable  to  injury.  Owing  to  the  heart  being  enclosed  in  the  peri- 
cardium,— a  closed  sac, — if  blood  accumulates  in  it  the  action  of  the  heart  is  inter- 


fered with.  To  avoid  this  occurrence,  wounds  bleeding  externally  should  not  be 
closed,  or  distention  of  the  pericardium  may  ensue. 

Wounds  of  the  heart  have  been  sutured  successfully.  In  order  to  reach  the 
heart,  a  portion  of  the  chest-wall  would  have  to  be  resected  and  turned  to  one  side 
as  a  flap.  This  will  probably  require  the  opening  of  the  pleural  cavity.  The  pleurse 
will  in  all  likelihood  already  have  been  involved  and  found  to  be  filled  with  blood,  as 
has  occurred  in  at  least  one  case. 

A  knowledge  of  the  exact  outlines  of  the  heart  as  already  given  will  often 
enable  one  to  decide  as  to  whether  a  wound  involves  the  heart  or  not. 


APPLIED    ANATOMY, 


THE  AORTA. 

The  aorta,  as  it  leaves  the  left  ventricle,  begins  under  the  left  portion  of  the 
sternum  opposite  the  lower  border  of  the  third  left  costal  cartilage.  This  is  the 
location  of  the  aortic  semilunar  valves  as  already  gi\en.  It  passes  upward  toward 
the  right  for  5  cm.  and  then  forms  an  arch,  extending  backward  toward  the  left,  to 
reach  the  spine  on  the  left  side  of  the  body  of  the  fourth  thoracic  vertebra.  The 
arch  is  continued  down  in  front  of  the  spine  as  the  thoracic  aorta  and  pierces  the 
diaphragm  in  the  median  line,  between  the  two  crura  of  the  diaphragm,  opposite  the 
twelfth  thoracic  \ertebra. 

The  ascending  aorta  begins  behind  the  left  half  of  the  sternum  on  a  level 
with  the  lower  border  of  the  third  costal  cartilage.  It  proceeds  upward  toward  the 
right  until  it  reaches  the  level  of  the  lower  border  of  the  right  second  costal  cartilage, 
where  the  arch  begins. 

Immediately  above  its  commencement  it  has  three  enlargements,  called  the 
sinuses  of  the  aorta  ( \'alsal\'a),  which  correspond  to  the  semilunar  valves.  Of 
the  three  semilunar  \-ahes  two  are  anterior  and  one  is  posterior.  From  behind  the 
two  anterior  \-ah'es  come  the  right  and  left  coronary  arteries. 

Be3'ond  the  valves,  in  the  upi)er  right  portion  of  the  arch,  the  aorta  is  again 
dilated,  forming  the  great  sinus  of  the  arch  of  the  aorta. 

The  right  limit  of  the  aorta  is  about  even  with  the  right  edge  of  the  sternum; 
sometimes  it  projects  slightly  beyond.  When  it  does  so  it  is  liable  to  be  wounded  by 
a  stab  in  the  second  interspace  close  to  the  edge  of  the  sternum.  On  account  of  the 
proximity  of  the  aorta  to  the  second  interspace,  it  is  here  that  the  stethoscope  is  placed 
to  hear  aortic  murmurs.  The  aorta  at  this  point  is  covered  only  by  the  thin  border  of 
the  right  lung  and  pleura  and  the  slight  remains  of  the  thymus  gland.  Below,  its  com- 
mencement is  o\erlapped  on  the  right  b)-  the  auricula  de.xtra  (right  auricular  appendix) 
of  the  atrium  and  on  the  left  by  the  commencement  of  the  pulmonary  artery. 

The  ascending  aorta  is  liable  to  be  the  seat  of  aneurism.  It  may  involve  either 
the  lower  portion  in  the  region  of  the  sinuses  or  the  region  of  the  great  sinus  at  its 
upper  right  anterior  portion. 

If  the  aneurism  enlarges  anteriorly  it  will  show  itself  first  in  the  second  or  third 
interspace.  It  will  bulge  the  ribs  outward  in  this  region.  The  right  lung  will  be 
pushed  outward  and  the  two  layers  of  the  pleura  pressed  together.  It  may  break 
externally  through  the  surface  or  open  into  the  pleural  cavity.  If  it  tends  to  the 
right  it  presses  on  the  descending  cava  and  right  atrium,  thus  interfering  with  the 
return  of  the  blood  from  the  head  and  neck  and  both  upper  extremities.  If  it  en- 
larges to  the  left  or  backward  it  may  press  on  the  right  pulmonary  artery  and 
interfere  with  the  free  access  of  blood  to  the  lungs. 

The  first  portion  of  the  aorta  is  not  united  with  the  pericardium,  but  simply 
loosely  covered  by  it,  so  that  this  portion  of  the  arch  is  weaker  than  the  other  por- 
tions, and  rupture,  with  extra^-asation  of  blood  into  the  pericardial  sac,  is  not  uncom- 
mon.     An  aneurism  may  also  rupture  into  the  superior  vena  cava. 

The  arch  of  the  aorta  passes  anteroposteriorh'  from  the  upper  border  of  the 
second  right  costal  cartilage  in  front  to  the  left  side  of  the  body  of  the  fourth  thoracic 
vertebra  behind.  It  is  about  5  cm.  (2  in. )  long.  Its  under  surface  is  level  with  the 
angle  of  the  sternum  (angle  of  Ludwig),  opposite  the  second  costal  cartilage.  Its 
upper  surface  rises  as  high  as  the  middle  of  the  first  piece  of  the  sternum,  which  is 
opposite  the  middle  of  the  first  costal  cartilage,  about  2.5  cm.  (i  in.)  below  the  top 
of  the  sternum. 

Relations. — In  front  of  the  arch  the  right  lung  and  pleura  co\-er  it  slightly,  but 
the  left  more  so;  the  remains  of  the  thymus  gland  is  between  them.  The  left  superior 
intercostal  vein  crosses  its  upper  portion  to  empty  into  the  left  innominate  vein.  The 
left  phrenic  and  vagus  nerves  also  cross  it,  the  phrenic  being  the  farther  forward  and 
the  vagus  crossing  almost  in  front  of  the  point  of  origin  of  the  left  subclavian  artery. 
Behind  lie  the  trachea,  oesophagus,  and  thoracic  duct,  also  the  left  recurrent  laryn- 
geal ner\-e.  The  bifurcation  of  the  trachea  is  directl)-  behind  and  below  the  lower 
portion  of  the  arch  and  the  left  bronchus  passes  beneath  it.      The  oesophagus  lies 


THE   AORTA. 


209 


compressed  between  the  trachea  and  vertebrje  with  the  thoracic  duct  immediately  to 
the  left.  The  left  recurrent  laryngeal  leaves  the  pneumogastric  on  the  front  of  the 
arch,  then  winds  around  it  and  ascends  between  the  trachea  and  oesophagus  to  reach 
the  larynx  abo\-e.  Above,  from  the  upper  surface  of  the  aorta,  are  given  oft  the 
innominate,  left  carotid,  and  left  subclavian  arteries.  The  left  innominate  vein  crosses 
above  its  upper  edge  to  unite  with  the  right  innominate  to  form  the  superior  cava. 
Below  is  the  left  bronchus  coming  off  from  the  bifurcation  of  the  trachea,  and  wind- 
ing around  the  arch  is  the  left  recurrent  laryngeal  nerve.  Beneath  the  arch  and 
in  front  of  the  bronchi  are  the  right  and  left  pulmonary  arteries.  From  the  latter  the 
ductus  arteriosus  goes  to  the  arch.  The  cardiac  branches  of  the  pneumogastric  and 
sympathetic  ner\'es  lie  on  the  anterior,  inferior,  and  posterior  sides  of  the  arch. 


nteraal 

Subclavian 
Innominate  artery. 
Right  recurrent 
laryngeal 
Right  innominate 


Vagus 

■Common  carotid  artery 

Internal  jugular  vein 

Subcia 


Left  coronary'  artery 
Left  ventricle 


-Heart  and  great  blood-vessels. 


The  ductus  arteriosus  at  birth  is  about  i  cm.  long  and  runs  from  the  pulmo- 
nary artery  to  the  arch  of  the  aorta  below  the  left  subclavian  artery.  It  serves  in  the 
fcetus  to  carry  the  blood  from  the  trunk  of  the  pulmonary  artery  direct  to  the  aorta 
instead  of  passing  into  the  lungs.  When,  after  birth,  the  lungs  are  used  the  ductus 
arteriosus  becomes  obliterated  and  is  found  later  in  life  as  a  cord  running  to  the 
under  side  of  the  arch  of  the  aorta.  Congenital  defects  in  the  heart  are  a  frequent 
cause  of  death  at  birth  and  in  infancy  and  childhood.  They  cause  an  undue  mi.xture 
of  the  \'enous  and  arterial  blood  and  give  the  surface  a  dusky,  bluish  hue,  hence  the 
term  ' '  blue  baby  ' '  as  applied  to  this  condition.  It  is  due  to  an  absence  of  a  part 
r4 


2IO  APPLIED    ANATOMY. 

or  the  whole  of  the  septa  between  the  atria  and  ^■entricles;  to  a  patulous  condition  of 
the  foramen  ovale  of  the  right  atrium  ;  and  also  to  a  persistent  patulous  condition  of 
the  ductus  arteriosus.  Children  so  affected,  if  they  outlive  infancy,  usually  die  before 
reaching  adult  age. 

Aneu7-ism. — This  portion  of  the  aorta  is  also  a  favorite  seat  of  aneurism.  The 
symptoms  produced  will  depend  of  course  on  the  direction  which  the  tumor  takes. 
If  it  tends  anteriorly  it  would  involve  the  lungs  and  pleurae  and  the  phrenic  and  vagus 
ner\'es,  also  the  sympathetic.  The  displacement  of  the  left  lung  would  be  the  more 
marked.  In\'oh'ement  of  the  recurrent  laryngeal  ner\-e  might  make  a  change  in  the 
voice,  or  there  might  be  disturbances  of  the  pupil  of  the  eye  due  to  implication  of 
the  sympathetic. 

Should  the  tumor  enlarge  posteriorly  the  pressure  on  the  trachea  would  inter- 
fere with  the  breathing.  If  the  tumor  is  large  this  pressure  would  invoh-e  the  oesoph- 
agus and  there  might  be  difficulty  in  s^^■allowing.  Compression  of  the  thoracic  duct 
is  said  to  have  led  to  rapid  wasting. 

If  the  aneurism  bulges  downward  it  impinges  on  the  left  bronchus,  which  may 
lead  to  its  dilation  and  cause  bronchorrheea.  A  large  tumor  could  also  interfere  with 
the  flow  of  blood  through  the  pulmonary  arteries  and  so  give  rise  to  congestion  and 
dyspncea. 

An  enlargement  upward  would  in\-ol\-e  the  innominate  and  left  carotid  and 
subclavian  arteries  and  also  the  left  innominate  vein.  Interference  with  the  arteries 
and  veins  of  the  neck  and  upper  extremity  frequently  gives  rise  to  changes  in  the 
pulse  on  the  affected  side  and  also  to  venous  congestion  or  even  oedema.  Changes 
in  the  voice  or  e\-en  its  loss  also  occur.  The  sac  as  it  passes  upward  may  show 
itself  in  the  suprasternal  notch. 

In  all  aneurisms  of  the  arch  cough  is  apt  to  be  a  prominent  symptom.  It  is 
often  paro.xysmal.  It  is  to  be  accounted  for  by  pressure  on  the  trachea  or  laryngeal 
nerves.  Difficulty  in  breathing  and  swallowing  may  arise  in  deep-seated  small  tumors 
growing  backward  and  down\\-ard.  This  may  be  somewhat  relieved  by  sitting  up  or 
leaning  for\vard,  while  reclining  or  lying  on  the  back  may  be  unendurable. 

The  great  amount  of  distress  which  these  aneurisms  of  the  arch  of  the  aorta  may 
give  rise  to  is  readily  appreciated  when  one  recalls  that  there  is  only  a  distance  of  5 
or  6  cm.  (23^4  in.)  between  the  upper  edge  of  the  sternum  and  the  anterior  surface 
of  the  vertebral  column,  a  space  alread}^  filled  with  important  structures. 

The  Descending  Aorta. — The  remaining  portion  of  the  aorta,  from  the  lower 
border  of  the  fourth  thoracic  vertebra  down,  is  called  the  descending  aoiia.  It  is 
divided  into  the  thoracic  and  abdominal  portions.  The  thoracic  aorta  begins  at  the 
lower  border  of  the  fourth  and  ends  at  the  lower  border  of  the  twelfth  thoracic 
vertebra.  At  its  beginning  it  lies  on  the  left  side  of  the  vertebral  column,  but  as  it 
descends  it  comes  somewhat  forward  but  does  not  reach  the  middle  line.  It  lies  in 
the  posterior  mediastinum  more  toward  the  left  side  than  toward  the  right. 

Relations. — In  front  abo^'e  are  the  pericardium,  the  pulmonary  artery,  left  bron- 
chus, left  pulmonary  veins,  and  oesophagus.  Behind  is  the  \-ertebral  column.  To 
the  right  are  the  cesophagus  abo\e,  the  xexva.  azvgos  major,  and  the  thoracic  duct. 
To  the  left  are  the  left  lung  and  the  pleura,  which  it  grooves,  and  a  quite  small 
portion  of  oesophagus  below. 

A)ieurism,  when  in^'ohing  the  thoracic  aorta,  tends  to  cause  absorption  of  the 
vertebrse  and  ribs,  and  to  present  posteriorly;  as  the  space  is  not  so  restricted  as  is 
the  case  higher  up  the  tumor  has  a  freer  opportunity  to  e.xpand  and  the  sufifering  is 
not  so  great  nor  are  the  svmptoms  so  marked.  It  may  rupture  into  the  left  pleura  or 
oesophagus  and  mav  erode  through  the  bodies  of  the  veriebrje  into  the  spinal  canal. 

These  aneurisms  may  e.xist  many  years  and  attain  a  large  size. 


THE    CESOPHAGUS. 


THE  OESOPHAGUS. 

The  oesophagus  begins  at  the  lower  edge  of  the  cricoid  cartilage,  opposite  the 
lower  border  of  the  sixth  cervical  vertebra,  and  ends  at  the  cardiac  opening  of  the 
stomach,  opposite  the  eleventh  thoracic  vertebra. 

It  is  25  cm.  ( 10  in.  )  long  and  begins  15  cm.  (6  in.  )  distant  from  the  teeth.  In 
the  neck  it  inclines  to  the  left,  hence  cesophagotomy  is  performed  on  that  side.  It 
reaches  the  farthest  point  to  the  left  at  the  level  of  the  top  of  the  sternum  or  oppo- 
site the  second  thoracic  vertebra.  It  then  inclines  to  the  right,  reaching  the  median 
line  opposite  the  fifth  thoracic  vertebra.  It  then  again  inclines  to  the  left,  to  pierce 
the  diaphragm  in  front  of  the  aortic  opening  and  to  the  left  of  the  median  line  opposite 
the  tenth  thoracic  vertebra,  and  ends  in  the  cardiac  opening  of  the  stomach  entirely 
to  the  left  of  the  median  line  and  opposite  the  eleventh  thoracic  vertebra  or  tenth 
dorsal  spine.  In  its  passage  through  the  diaphragm  it  is  accompanied  by  the  con- 
tinuation of  the  two  vagi  nerves.  At  its  termination  it  grooves  the  posterior  surface 
of  the  liver. 

Lumen. — The  lumen  of  the  oesophagus  is  narrowed  at  three  points,  (i)  its  com- 
mencement; (2)  where  it  crosses  the  aorta  and  left  bronchus;  and  (3)  near  its  end 
as  it  passes  through  the  diaphragm. 

The  average  diameter  of  the  lumen  is  2  cm. ,  which  at  the  upper  and  lower 
constrictions  is  reduced  to  1.5  cm.  The  middle  constriction  is  not  quite  so  marked. 
The  lower  constriction  is  most  marked  at  the  point  of  the  passage  of  the  oesophagus 
through  the  diaphragm;  it  enlarges  slightly  as  it  enters  the  stomach.  This  part  of 
the  oesophagus  is  quite  chstensible.  The  ne.xt  most  distensible  part  is  opposite  the 
left  bronchus.  This  is  on  a  level  with  the  middle  of  the  first  piece  of  the  sternum  and 
the  third  thoracic  vertebra.  The  upper  constriction  at  the  cricoid  cartilage  is  the 
least  distensible  part  of  the  tube,  so  that  a  body  passing  it  may  pass  entirely  down. 

In  both  living  and  dead  bodies  the  lumen  of  the  oesophagus  is  sometimes  open 
and  sometimes  closed.  In  the  neck  the  pressure  of  the  soft  parts  usually  keeps  it 
closed,  but  frozen  sections  of  the  dead  body  show  it  sometimes  closed  and  sometimes 
open.  Mikulicz  in  using  the  oesophagoscope  has  found  the  lumen  open  in  the  living 
patient  and  been  able  to  see  down  the  remainder  of  the  tube  when  the  instrument  has 
only  been  passed  beyond  the  second  constriction. 

In  passing  an  oesophageal  bougie,  one  should  not  be  used  of  a  larger  diameter 
than  18  mm.  (3^  in.).  It  will  enter  the  oesophagus  opposite  the  lower  border  of  the 
cricoid  cartilage  about  15  cm.  (6  in.)  from  the  teeth.  It  will  pass  the  second  con- 
striction 7  cm.  (2  3<|  in.)  farther  on,  opposite  the  middle  of  the  first  piece  of  the 
sternum  or  2.5  cm.  (i  in.)  below  its  upper  border,  and  meet  the  third  constriction 
15  cm.  (6  in.)  lower  down,  or  37  cm.  (14.4  in. )  from  the  teeth,  and  enter  the  stomach 
3  cm.  below,  or  40  cm.  (16  inches)  from  the  teeth  and  opposite  the  eleventh  dorsal 
vertebra. 

Relations. — In  the  neck  the  oesophagus  rests  on  the  longus  colli  muscle  and 
vertebree  behind  and  has  the  trachea  in  front.  On  the  left  side  it  lies  close  to  the 
carotid  sheath,  the  lobe  of  the  thyroid  gland,  and  the  thoracic  duct.  The  left  recurrent 
laryngeal  nerve  is  in  closer  relation  to  it  than  the  right  on  account  of  the  latter 
coming  over  from  the  right  subclavian  artery.  The  left  nerve  lies  on  its  anterior 
surface  near  the  left  edge.  The  right  carotid  artery  lies  farther  from  it  than  does 
the  left.  The  left  inferior  thyroid  artery  is  also  in  closer  relation  to  it  than  the  right 
on  account  of  the  inclination  of  the  oesophagus  to  the  left  side. 

In  the  thorax  it  passes  through  the  superior  mediastinum  between  the  trachea  and 
its  bifurcation  in  front  and  the  aorta  behind. 

In  front  it  has  the  bifurcation  of  the  trachea  and  encroaches  more  on  the  left 
than  on  the  right  bronchus.  The  arch  of  the  aorta  and  the  left  carotid  and  subclavian 
arteries  also  pass  in  front  of  it  and  in  the  posterior  mediastinum  the  pericardium  and 
diaphragm  are  anterior  to  it. 

Posteriorly,  above  it  rests  on  the  spinal  column,  but  below  the  bifurcation  of 
the  trachea  the  aorta  intervenes. 


APPLIED    ANATOMY. 


Laterally  it  is  in  relation  with  the  left  pleura  above  and  the  right  below  and  the 
vena  azygos  major  runs  along  its  right  side  posteriorly.  The  arch  of  the  aorta  winds 
around  its  left  side  at  the  root  of  the  lung.  The  right  vagus  nerx-e  runs  down  pos- 
teriorly and  the  left  anteriorly,  forming  a  plexus  on  its  surface. 

Dilatation  and  Diverticula. — In  certain  rare  cases  the 
oesophagus  becomes  dilated  ;  this  ma^r  involve  the  whole  length 
of  the  tube  or  only  its  lower  end.  Obstruction  low  down  may  be 
a  cause.  It  has  been  known  to  accompany  a  largely  dilated  aorta 
which  pressed  the  cesophagus  against  the  diaphragmatic  opening 
and  so  hindered  the  passage  of  food.  Regurgitation  of  food  is  a 
prominent  symptom  and  liquids  may  regurgitate  from  the  stomach 
and  even  enter  the  mouth. 

Diverticula  are  usually  acquired  and  are  but  seldom  con- 
genital. The  point  of  junction  with  the  pharynx  just  behind  the 
cricoid  cartilage  is  the  most  frequent  seat.  A  sac  is  formed  which 
descends  posteriorly  behind  the  part  of  the  tube  below  and  as  it 
increases  in  size  it  presses  forward  and  may  obstruct  its  lumen. 
Obstruction  from  foreign  bodies,  stricture,  or  disease  of  the  cardiac 
end  of  the  stomach  may  be  a  cause.  Vomiting  is  a  prominent 
symptom  and  the  vomited  material  does  not  show  any  e^■idences  of 
digestion  or  the  presence  of  acid.  The  existence  of  a  tumor  which 
forms  only  on  deglutition  and  which  can  be  emptied  by  pressure 
is  said  to  be  pathognomonic  of  an  oesophageal  cli\-erticulum. 

Di\'erticula  have  been  treated  by  washing  out  with  a  stomach- 
tube,  by  excision,  or  if  emaciation  is  rapid  and  marked  by  doing 
a  gastrostomy. 

Carcinoma  and  Stricture. — Carcinoma  is  usually  of  a  fiat- 
celled  epitheliomatous  t)-pe  and  may  surround  the  oesophagus  like 
a  ring.  The  walls  are  thickened,  a  tumor  forms,  and  the  internal 
surface  may  become  ulcerated.  Stricture  of  the  affected  part  may 
lead  to  the  formation  of  a  dilation  or  diverticulum  above,  and  ulcer- 
ation and  abscess  may  perforate  and  enter  surrounding  organs. 

Dyspnoea  may  arise  from  pressure  on  the  air-passages  and  pus 
may  even  penetrate  them.  Hemorrhage  is  also  sometimes  a  symp- 
tom. It  may  come  either  from  the  inside  or  outside.  In  the  latter 
case  it  may  come  from  the  large  \'essels  in  the  neighborhood. 

Septic  inflammation  may  also  be  set  up  in  the  adjacent  pleuree 
and  lungs. 

Foreign  Bodies. — Foreign  bodies  may  become  impacted 
at  any  part  of  its  course;  this  is  particularly  the  case  if  they  are 
hard  and  rough  with  irregular  outlines.  If  they  are  smooth  and 
soft  and  more  or  less  rounded  they  are  apt  to  lodge  at  the  con- 
stricted parts  of  the  tube.  These  points  are,  as  already  stated,  at 
its  commencement,  where  it  crosses  the  aorta  and  left  bronchus, 
and  where  it  passes  through  the  diaphragm.  The  upper  con- 
striction is  1.5  cm.  (or  f  in.)  in  diameter,  and  is  least  distensible. 
It  will  dilate  to  the  width  of  2  cm. ,  and  thus  will  allow  a  body  of 
about  |<4  inch  diameter  to  pass.  The  two  lower  constrictions  are 
more  distensible  and  a  body  that  passes  the  cesophagus  can  usually 
pass  the  ileocsecal  valve,  so  that  the  upper  end  of  the  oesophagus 
acts  as  a  gauge  to  prevent  the  entrance  of  substances  too  large  for 
the  rest  of  the  alimentary  tract.  The  bodies  which  become  lodged 
are  usually  those  which  have  been  pushed  down  beyond  the  open- 
ing of  the  cesophagus  by  the  contraction  of  the  muscles  of  the 
pharynx,  and  then  on  account  of  their  irregular  form  become 
1-  caught  by  the  contraction  of  the  tube  below.  With  the  head  mod- 
erately extended,  the  first  constriction  will  be  15  cm.  (6  in.)  from 
the  teeth.  A  foreign  body  at  this  point  will  be  opposite  the  cricoid  cartilage  at  the 
level  of  the  sixth  cervical  vertebra. 


t 


Fig.  22,5.- 
gtis.  From 


THE    (ESOPHAGUS. 


^13 


The  second  constriction  is  opposite  the  middle  of  the  hrst  piece  of  the  sternum. 
This  is  7  cm.  (2  3^  in.)  below  the  cricoid  cartilage.  Therefore  a  foreign  body  lodged 
just  above  it  would  be  just  below  the  top  of  the  sternum. 

It  would  be  felt  by  the  probe  22  cm.  (Si  in.  )  from  the  upper  teeth  and  if  cesopha- 
gotomy  was  performed  it  could  usually  be  reached  from  the  wound  in  the  neck. 

The  third  constriction  is  15  cm.  (6  in.)  below  the  second,  or  37  cm.  (14!  in.) 
from  the  teeth,  and  is  accessible  from  the  stomach.      This  third  constriction  is  more 


Int.  jugular  vein 

Vagus  nerve 
Common  carotid  artery 
Inf.  thyroid  artery- 
Vertebral  artery 
"Trachea 
-Recurrent  laryngeal 

CEsophagus 
Right  vagus  nerve 

Vena  azygos 

major 

Right  bronchus 

Right  pulmonary 

artery 

Pulmonary'  vein 


Pulmonary 


Thoracic  duct 


Vena  azygos 
major 


ding  structures. 


distensible  than  the  two  above  it.  Maurice  H.  Richardson  was  able,  after  introducing 
the  hand  into  the  stomach,  to  put  two  fingers  into  the  cardiac  opening  from  below, 
and  so  dislodge  some  impacted  false  teeth. 

Foreign  bodies  are  dangerous  on  account  of  the  ulceration  into  the  various  organs 
which  they  cause  and  also  on  account  of  pressure.  Pressure  on  the  left  bronchus  and 
trachea  has  caused  suffocation. 


214  APPLIED    ANATOMY. 

Ulceration  may  cause  fatal  hemorrhage  by  invoh'ing  the  carotid  arteries,  more 
likely  the  left,  the  inferior  thyroids,  the  innominate,  and  e\-en  the  aorta  itself  lower 
down.  Low  down  in  the  chest  the  pericardium  is  in  front  of  the  oesophagus,  and 
has  been  perforated.  On  the  left  side  above  and  the  right  side  below,  the  pleurae 
have  been  perforated  and  the  lungs  involved.  Abscesses  may  occur  from  the  ulcer- 
ative process  and  they  are  particularly  dangerous,  as  the  distance  between  the  upper 
portion  of  the  sternum  and  anterior  portion  of  the  bodies  of  the  vertebrae  is  so  small 
that  compression  of  the  air-passages  and  suffocation  is  readily  produced. 

THE  THORACIC   DUCT. 

The  thoracic  duct  carries  not  only  lymph  but  also  chyle  which  is  emptied  into  the 
venous  system  and  goes  to  nourish  the  body.  Therefore  a  wound  of  the  duct  with 
the  escape  of  its  ffuid  may  result  fatally  from  inanition.  The  lymph  coming  from  all 
parts  of  the  body  is  collected  into  two  ducts,  the  right  lymphatic  duct  and  the  thoracic 
duct.  Of  these  two  the  right  lymphatic  duct  is  the  smaller.  It  collects  the  lymph 
coming  from  the  right  side  of  the  head  and  neck,  right  upper  extremity,  right  side  of 
the  thora.x  and  the  upper  conve.x  surface  of  the  liver.  The  several  lymphatic  branches 
unite  to  form  a  duct,  one  to  two  centimetres  long,  which  empties  into  the  venous 
system  at  the  junction  of  the  right  internal  jugular  and  subclavian  veins.  At  its  point 
of  entrance  it  is  guarded  by  a  pair  of  valves.  As  this  duct  contains  no  chyle,  and 
lymph  of  only  a  portion  of  the  body,  wounds  of  it  have  not  proved  serious. 

The  thoracic  duct  is  much  larger  and  more  important.  It  begins  on  the 
bodies  of  the  first  and  second  lumbar  vertebrae  to  the  right  of  the  aorta  in  the 
cisterna  (receptaculum^  chyli. 

The  cisterna  or  receptaculum  is  5  to  7.5  cm.  long  and  7  mm.  wide.  It  receives 
not  only  the  lymph  from  the  parts  below  but  also  the  chyle  from  the  intestines.  It 
passes  through  the  aortic  opening  in  the  diaphragm  with  the  aorta  to  the  left  and  the 
vena  azygos  major  to  the  right.  In  the  posterior  mediastinum  it  lies  on  the  bodies 
of  the  seven  lower  thoracic  \'ertebrae,  with  the  pericardium,  the  oesophagus,  and  the 
arch  of  the  aorta  in  front.  The  thoracic  aorta  is  to  its  left  and  the  vena  azygos  major 
and  right  pleura  to  its  right.  Above  the  fifth  thoracic  vertebra  it  ascends  between  the 
oesophagus  and  left  pleura,  behind  the  first  portion  of  the  left  subclavian  artery. 
On  reaching  the  level  of  the  seventh  cervical  vertebra  it  ciu'ves  downward  over  the 
left  pleura,  subclavian  artery,  scalenus  anticus  muscle,  and  vertebral  vein  to  empty 
at  the  junction  of  the  internal  jugular  and  left  subclavian  veins.  It  passes  behind 
left  internal  jugular  vein  and  common  carotid  artery.  At  its  termination  it  lies 
just  external  to  the  left  sternoclavicular  joint  and  just  below  the  level  of  the  upper 
border  of  the  clavicle.      A  punctured  wound  at  this  point  would  injure  the  duct. 

Accompanying  the  \'eins  of  the  neck  are  numerous  lymph-nodes  which  not 
infrequently  become  enlarged  and  require  removal.  It  is  in  operating  on  these  nodes 
that  wounds  of  the  thoracic  duct  have  been  most  often  produced.  When  divided,  its 
lumen  has  appeared  to  be  of  the  size  of  a  "knitting  needle."  In  some  instances  the 
thin  walls  of  the  duct  have  been  ligated.  In  other  cases  of  injury  either  the  oozing 
point  has  been  clamped  with  a  haemostatic  forceps  which  has  been  left  in  position  for 
a  day,  or  else  the  wound  has  been  packed  with  gauze.     Recovery  usually  ensues. 


THE   THORACIC   DUCT. 


215 


Internal  jugular  vein 

Trachea 

Vertebral 

Right  lymphatic  duct- 

Subclavian  vein 

I.  rib' 

Right  innominate 


CEsophagus. 


Vena  azygos- 


Right  lumbar  lymph  trunk 


Crest  of  ilium 


Left  common  carotid  artery 

Left  innominate  vein 

Thoracic  duct 

Left  subclavian  vein 

Scalenus  anticus 

Left  subclavian  artery 

Tliyroid  axis 

I.  rib 

Vertebral  artery 


■Thoracic  duct 


Intercostal  arteries 


Left  lumbar  lymph  trunk 


Fig.  225. — Dissection  of  posterior  body- wall,  seen  from  in  front,  showing  thoracic  duct  and  right  lymphatic  duct; 
vems  have  been  laterally  displaced  to  expose  the  terminations  of  the  thoracic  duct.     (Piersol.) 


2l6 


APPLIED    ANATOMY. 


THE  UPPER    EXTREMITY. 

Morphology. — The    human    skeleton   consists  of  two  parts,   called  the  axial 
skeleton  and  the  appendicular  skeleton. 

The  axial  skeleton  embraces  the  bones  of  the  head,  the 
spine,  the  ribs,  the  hyoid  bone,  and  the  breast  bone.  In  the 
spme  are  included  not  only  the  vertebrae  of  the  cervical, 
thoracic,  and  lumbar  regions,  but  likewise  the  sacrum  and 
cocc} \ 

The  appendiatlar  skeleton  embraces  the  bones  of  the  limbs, 

or  extiemities,  including  the  shoulder-girdle,  formed  by  the 

scapula  and  clavicle,  and  the  peh'ic 

girdle,  formed  by  the  innominate  bone 

(Fig.  226). _ 

Function. — The  upper  extrem- 
ity in  man  is  an  organ  of  prehension. 
As  such,  mobility  is  its  chief  charac- 
teristic. To  permit  of  this  mobility 
the  bones  and  joints  are  many,  and 
the  latter  are  comparatively  loose; 
the  muscles,  also,  are  both  numerous 
and  complex.  Hence  it  is  that  slight 
injuries  are  frequently  followed  by 
considerable  disturbance  of  function. 
They  are  readily  produced  and  with 
difficulty  repaired,  either  by  nature 
or  by  art.  Orthopgedic  surgery  has 
done  much  for  the  disabilities  and  de- 
formities of  the  lower  extremities,  but 
comparatively  little  for  those  of  the 
upper.  An  artificial  leg  in  many  cases 
satisfactorily  substitutes  the  natural 
one,  but  an  artificial  arm  is  compara- 
tively useless. 

The  hand  is  the  essential  part 
of  the  upper  extremity,  and  the  rest 
of  the  limb  is  subsidiary.  If  the  forearm  were  lack- 
ing and  the  hand  were  attached  to  the  end  of  the 
humerus  it  would  still  be  a  very  useful  appendage, 
far  more  so  than  the  stump  which  is  left  after  the  hand 
has  been  amputated. 

The  extremities  proper  are  joined  to  the  trunk  by 
what  are  called  girdles.  The  upper  extremity  is 
attached  through  the  medium  of  the  shoulder-girdle 
and  the  lower  extremity  by  the  pelvic  girdle.  The 
interposition  of  these  girdles  adds  to  the  mobility  of 
the  extremities,  and  as  the  upper  extremity  is  more 
mobile  than  the  loA\'er  we  find  the  shoulder-girdle  com- 
posed of  two  bones  instead  of  one  as  in  the  pelvic 
girdle  ;  also,  as  the  lower  extremity  bears  the  weight 
of  the  body  it  requires  strength  in  addition  to  mobility, 
hence  we  find  that  it  is  joined  to  the  trunk  by  a  single 
big  strong  bone,  the  innominate,  instead  of  by  two 
comparatively  slight,  narrow  bones  like  the  clavicle 
and  scapula  which  form  the  shoulder-girdle. 

The  extremities  are  termed  appendicular  because 
^r.?t''^'r.V'f'7''^'^''^S:"''^°\^'^^}'T^      they   are    simply   appendages  to  the   essential  part, 

and  trunk  torming  the  axial  skeleton  ..'        .  ,  ^  -^ ,      ^',  *!  1  •  ■  1. 

and  those  of  the  upper  and  lower  ex-      which  IS  the  head  and  trunk;  a  person  can  five  with- 

tremities  constituting  the  appendicu-  ^         ^  •..• 

lar  skeleton.  out  extremities. 


THE  SHOULDER-GIRDLE. 


THE  SHOULDER-GIRDLE. 

The  upper  extremity  is  joined  to  the  trunk  b}'  the  shoulder-girdle,  which  is 
composed  of  the  clavicle  and  scapula.  The  main  mo\ements  are  anteroposterior, 
as  in  swinging  the  arm,  those  of  abduction  and  adduction,  as  in  raising  and  lower- 
ing it  sidewise,  and  rotation. 

The  scapula  is  the  more  important  bone;  it  is  present  in  all  mammals,  and  the 
humerus  articulates  with  it. 

The  scapula  in  the  mole  and  many  other  animals  may  be  a  comparatively 
slender   bone,    but   when,  as   in   man,  it    is    necessary   to   rotate  the  arm,   then   the 


Acromion  process 


Fig.  227. — Shoulder-girdle  of  man. 

scapula  is  large  so  as  to  form  a  strong  support  for  the  infraspinatus,  supraspinatus, 
teres  minor  and  major,  and  subscapularis  muscles. 

The  clavicle  is  developed  mainly  from  membrane,  partly  probably  from  carti- 
lage, and  is  the  first  bone  in  the  body  to  ossify.  It  keeps  the  shoulder  out  away 
from  the  body  and  increases  the  range 
of  motion  of  the  upper  e.xtremity.  It 
owes  its  existence  to  the  function  of 
abduction.  Without  a  clavicle  abduc- 
tion is  practically  wanting  and  when  in 
man  the  clavicle  is  broken,  he  is  tem- 
porarily reduced  to  the  condition  of  those 
animals  which  have  no  clavicles;  he  is 
able  to  move  the  arm  backward  and  for- 
ward but  not  to  ele\'ate  it  properly,  and 
this  is  an  important  diagnostic  symptom 
of  that  injury. 

The  clavicle  is  lacking  in  the  ungu- 
lates or  hoofed  animals.  These  have  an 
anteroposterior  movement,  but  little  abduction.  A  horse  or  cow  mo\'es  its  fore-legs 
back  and  forward,  but  not  out  away  from  the  body.  Hence  its  helplessness  when 
these  movements  are  essential.  It  is  also  lacking  in  seals  and  whales.  In  the 
carnivora,  as  the  hon  and  the  tiger,  which  possess  rudimentary  clavicles,  sufficient 
adducting  power  is  present  to  enable  them  to  hold  their  food  while  tearing  it  apart. 
In  man,  apes,  bats,  rodents,  and  insectivora  the  clavicle  exists  as  a  well-formed  bone; 


Fig.  228. — Shoulder-girdle  of  man,  showing 
the  clavicle  acts  as  a  prop  to  keep  the  shoulder  out 
from  the  chest. 


2l8 


APPLIED    ANATOMY. 


hence  they  can  raise  the  arm  well  out  from  the  body  and  even  higher  than  the 
shoulder.  In  the  rodents,  as  the  squirrel,  they  are  enabled  to  hold  a  nut  firmly  in 
the  paws  whQe  eating  it.  When,  as  in  some  of  the  lower  orders,  the  function  of 
abduction  is  all  important,  we  find  not  only  the  clavicles  present  and,  as  in  the 
common  fowl,  joined,  forming  the  "wish-bone,"  but  in  addition,  in  birds,  there  is  a 
precoracoid  bone  formed  by  the  coracoid  process,  which  is  enlarged  and  continued 
forward  to  articulate  with  the  sternum;  thus  in  flying  animals  there  are  practically 
two  clavicles  on  each  side. 

Affections  of  the  Shoulder. — The  point  of  the  shoulder  projects  well  out 
from  the  side  of  the  thorax.      Hence  it  is  frequently  injured.     As  the  force  is  resisted 


Fig.  229. — Shoulder-girdle  in  birds.  Skeleton  of  an  eagle,  from  the  Wistar  Institute:  the  clavicle,  precoracoid, 
and  scapula  form  the  shoulder-girdle;  the  two  clavicles  have  fused  in  the  median  line,  forming  what  is  commonly- 
called  the  "  wish-bone." 


by  the  bones,  these  receive  the  principal  injuries  and  they  are  often  broken.  Frac- 
tures of  the  clavicle  dispute  with  those  of  the  radius  the  distinction  of  being  the 
most  numerous.  Contusions  produce  more  or  less  complete  paralysis  of  the  muscles, 
not  infrequently  through  lesions  of  the  ner\'es.  The  laxity  of  the  joint  favors  the 
dislocations  to  which  it  is  so  frequently  subject.  It  likewise  becomes  the  seat  of 
tuberculous  disease  requiring  resection.  Crushes  of  the  arm  sometimes  require  its 
removal  at  the  shoulder-joint,  and  occasionally  as  the  result  of  injury  or  disease  opera- 
tions may  be  required  on  the  axillary'  lymph-nodes,  ner^^es,  or  blood-vessels. 

In  order  to  determine  the  character  and  extent  of  injuries  to  the  shoulder,  its 
surface  anatomy  must  be  thoroughlv  known.  In  order  to  treat  them,  a  knowledge 
of  the  deeper  structures  and  their  relation  to  one  another  is  essential. 


THE  SHOULDER-GIRDLE. 


219 


The  landmarks  of  the  shoulder  are  formed  by  the  bones  and  muscles;  hence  a 
brief  review  of  their  important  characters  will  serve  as  a  basis  for  the  surface  anatomy 
which  follows. 

THE    BONES    OF    THE   SHOULDER. 

The  bones  entering  into  the  construction  of,  and  forming  the  basis  on  which  the 
shoulder  is  constructed  are  the  clavicle  and  scapula,  forming  the  shoulder-girdle,  and 
the  humerus. 

The  clavicle  is  a  comparatively  long  and  slender  bone  that  acts  as  a  prop  to 
keep  the  point  of  the  shoulder  out  from  the  trunk.  The  inner  extremity  is  large  and 
rests  with  its  flat  surface  on  the  upper  outer  edge  of  the  sternum,  with  the  inter- 
position of  a  disk  of  fibrocartilage.     Its  outer  extremity  is  flattened  ;  it  articulates  by 


=^  ^  1  Sternal 


Pectoralis  major 


Fig.  230. — Right  clavicle,  upper  surface. 


means  of  a  gliding  joint  with  the  acromion  process  of  the  scapula,  and  it  is  connected 
with  the  base  of  the  coracoid  process  beneath  by  ligaments.  It  is  double  curved,  the 
large  cur\re  having  its  convexity  forward  and  embracing  the  inner  two-thirds  of  the 
bone,  and  the  small  curve  having  its  concavity  forward,  forming  the  outer  third. 

At  the  deepest  part  of  the  concavity  of  the  anterior  edge,  about  at  the  junction 
of  its  outer  and  middle  thirds,  is  a  small  rough  eminence  called  the  deltoid  tubercle 
because  of  the  attachment  to  it  of  the  deltoid  muscle.  At  a  corresponding  point  on 
the  posterior  and  under  surface  of  the  bone  is  a  prominent  projection  called  the  conoid 
tubercle ;  to  this  is  attached  the  conoid  ligament.  Running  forward  and  outward 
from  this  tubercle  on  the  under  surface  is  a  rough  line  which  serves  as  the  point  of 


Fig.  231. — Right  clavicle,  under  surfacs. 


Sternohyoid 


attachment  of  the  trapezoid  ligatneiit.  Both  these  ligaments  are  of  importance  in 
relation  to  the  fractures  of  this  bone. 

The  middle  third  of  the  bone  is  its  weakest  part.  Attached  to  the  clavicle  on 
its  anterior  surface  are  the  deltoid  mtcscle  on  its  outer  third  and  the  pectoralis  major 
on  its  inner  half.  On  its  posterior  and  upper  surfaces  are  the  trapezius  at  its  outer 
third,  and  the  clavicular  head  of  the  stcrnomastoid  on  its  inner  third.  The  subclavius 
muscle  is  attached  to  its  under  surface.  It  will  thus  be  seen  that  there  is  a  space  equal 
to  one-si.xth  of  the  length  of  the  bone  inferiorly  and  one-third  of  the  bone  superiorly 
which  is  free  from  muscular  attachments,  and  it  is  here  that  it  is  most  frequently 
fractured. 

The  Scapula. — The  scapula  is  spoken  of  as  having  a  body,  neck,  spine,  and 
acromion ,  glenoid,  and  coracoid  processes ;  an  upper,  an  anterior,  and  a  posterior  border ; 
and  an  upper  and  a  lower  angle.  It  is  not  often  spoken  of  as  possessing  a  head,  the 
glenoid  process  or  that  portion  being  sometimes  so  called  in  which  the  glenoid  cavity 
or  fossa  for  the  articulation  of  the  humerus  is  situated. 


220  APPLIED    ANATOMY. 

The  constriction  surrounding  the  head  of  the  scapula  is  known  as  the  anato7nical 
7ieck,  in  contradistinction  to  the  surgical  neck,  which  name  has  been  given  to  that 
portion  indicated  by  a  hne  drawn  through  the  suprascapular  notch  and  passing 
beneath  the  spine  and  to  the  inside  of  the  attachment  of  the  long  head  of  the  triceps 
muscle  just  below  the  lower  edge  of  the  glenoid  cavitv. 

The  angles  and  borders  and  spine  are  important  landmarks  in  physical  diagnosis 
and  the  coracoid  and  acromion  processes  in  injuries. 

In  the  upper  border  of  the  bone  at  its  junction  with  the  base  of  the  coracoid 
process  is  a  deep  notch  called  the  suprascapular  notch  {incisura  scapulcs),  the  supra- 


Levator  scapul 


Short  head  of 
biceps  and  coraco- 
brachialis 


Fig.  232. — Scapula,  showing  muscular  attach 


scapular  nerve  passes  through  it.  The  arterv  passes  o\'er  it.  From  the  edge  of  the 
bone  just  behind  the  notch  arises  the  omohyoid  muscle,  an  important  guide  in  opera- 
tions on  the  neck. 

The  body  of  the  scapula  on  its  under  surface  is  flat  and  rests  on  the  thorax  from 
the  second  to  the  seventh  and  nearly  to  the  eighth  rib.  Its  movements  on  the  chest 
are  free  and  follow  those  of  the  arm.  It  rises  and  falls,  glides  forward  and  backward, 
and  also  rotates  on  an  anteroposterior  axis. 

When  using  any  portion  of  the  scapula  as  a  landmark  it  is  customary  to  have 
the  arm  hanging  by  the  side;  if  it  is  otherwise  the  position  of  the  bone  will  be 
changed,  and  the  relations  of  its  projections  to  the  surrounding  parts  are  altered. 
The  scapula  is  sometimes  fractured  directly  across  its  body  below  the  spine.  One 
should  endeavor  to  fix  in  mind  especially  the  relation  of  the  acromion  and  coracoid 
processes  to  the  head,  with  its  glenoid  cavity,  and  the  rest  of  the  bone. 


THE  SHOULDER-GIRDLE. 


Greater  tuberosity 
Lesser  tuberosity 
facet  for  subscapu- 
laris  muscle 

Bicipital  groove 


-Anterior  surf  ace  of  upper  end  of  hu 


The  head  is  comparatively  small  and  cup-shaped,  with  the  glenoid  fossa  on  its 
surface  for  the  head  of  the  humerus.  It  is  joined  to  the  body  of  the  bone  by  a  narrow- 
constriction  called  the  neck.  Fractures  through  this  neck  are  rare.  Above  and  pos- 
terior to  the  glenoid  fossa  is  the  acromion  process  and  spine  of  the  scapula,  and  above 
and  anterior  is  the  coracoid  process. 

The  spine  of  the  scapula  runs  upward  and  forward  across  the  upper  and  posterior 
surface  of  the  bone.     Its  commencement  ,  ... 

at  the  posterior  edge  of  the  bone  is  called 
its  root;  this  is  o\'er  the  fourth  rib  and 
opposite  the  third  thoracic  spine.  The 
posterior  edge  of  the  scapula  opposite 
the  root  of  the  spine  projects  backward, 
but  this  is  not  the  superior  angle,  which  is 
still  higher  up.  The  spine  of  the  scapula 
ends  anteriorly  in  the  acromion  process. 
This  projects  far  beyond  the  glenoid  cav- 
ity, overhangs  the  head  of  the  humerus, 
and  forms  the  point  of  the  shoulder.  It, 
as  well  as  the  rest  of  the  spine,  is  subcu- 
taneous and  is  a  valuable  landmark. 

The  acromion  process  is  not  so  often 
fractured  as  one  would  e.xpect.  It  articu- 
lates with  the  clavicle  and  the  bones  are 
not  infrequently  luxated  at  this  point. 

The  coracoid  process  projects 
forward  underneath  the  clavicle  to  the 
upper  and  inner  side  of  the  head  of  the 
humerus.  It  is  about  2.5  cm.  (i  in.) 
below  the  clavicle  and  just  to  the  outer 
side  of  the  junction  of  its  middle  and  outer  thirds.  It  lies  just  underneath  the  inner  edge 
of  the  deltoid  muscle,  hence  it  is  not  always  easily  felt.  It  is  almost  never  fractured, 
but  is  especially  valuable  as  a  landmark  in  injuries  and  operations  on  the  shoulder. 

The  two  great  hollows  abo\-e  and  below  the  spine  are  the  supra-  and  infraspinojis 
fosses  for  the  supra-  and  infraspinatus  muscles.    The  angles  are  at  the  two  extremities 

of  the  posterior  border.  The 
superior  angle  receives  the  in- 
sertion of  the  levator  scapulae 
muscle  and  is  covered  by  the 
trapezius  which  inserts  into  the 
spine  and  thus  obscures  its  out- 
line. The  inferior  angle  is  cross- 
ed by  the  upper  edge  of  the 
/atissinuis  dor  si  muscle,  from 
which  it  sometimes  receives  a 
few  fibres.  This  angle  is  ren- 
dered prominent  when  the  fore- 
arm is  flexed  on  the  arm  and 
placed  across  the  back. 

The  Humerus  . — The 
upper  end  of  the  humerus  is 
composed  of  a  head  joined  to 
the  tuberosities  through  the 
medium  of  the  anatomical  neck. 
The  head  projects  inwardly  from 
the  shaft  at  an  angle  of  1 20  degrees  to  it.  The  lesser  tuberosity  has  inserted  into  it 
the  subscapiilaris  muscle;  it  presents  forward.  To  its  outer  side  and  separating  it 
from  the  greater  tuberosity  is  the  bicipital  groove  for  the  long  tendon  of  the  biceps 
muscle.  To  the  outer  side  of  the  groo\-e  is  the  greater  tuberosity  with  its  three  facets 
for  the  supi^aspinatus,  infraspinatus,  and  teres  minor  muscles. 


Anatontical  neck 
Facet  for  infra- 
spinatus muscle 
Facet  for  teres 
minor  muscle 

Surgical  neck 


Facet  for  supra- 
pinatus  muscle 
Bicipital  groove 

Greater  tuberosity 
tuberosity 


of  upper  end  of  h 


222  APPLIED    ANATOMY. 

The  greater  tuberosity  projects  considerably  beyond  the  acromion  process  and 
therefore  forms  the  most  prominent  part  of  the  shoulder.  Immediately  below  the 
tuberosities  is  the  surgical  neck.  It  is  described  as  being  the  portion  between  the 
tuberosities  above  and  the  insertions  of  the  pectoralis  major  and  latissimus  dorsi 
muscles  below.  It  is  a  common  site  for  fractures.  Half  way  down  the  shaft  on  its 
outer  side  is  the  rough  deltoid  eminence  for  the  insertion  of  the  deltoid  muscle. 

Sternoclavicular  Joint. — The  ligaments  uniting  the  inner  end  of  the  clavicle 
to  the  thorax  at  the  upper  end  of  the  sternum  are  the  interclavicular,  which  passes 
from  one  clavicle  to  the  other  across  the  top  of  the  sternum,  the  antei'ior  s^nd posterior 
sternoclavicular,  and  the  rhomboid  or  costoclavicular  ligajnent  which  passes  from  the 
clavicle  downward  and  forward  to  the  first  rib.  This  last  one  limits  displacement  in 
cases  of  lu.xation.  There  is  a  fibrocartilaginous  disk  between  the  clavicle  and  sternum, 
forming  two  distinct  joint  cavities.    The  line  of  the  joint  slopes  downward  and  outward. 

Acromioclavicular  Joint. — The  outer  end  of  the  clavicle  articulates  with  the 
acromion  process  by  a  joint  whose  surface  inclines  down  and  inward,  thus  favoring 
displacements  of  the  clavicle  upward.  The  ligaments  joining  them  are  called  the 
supej'ior  and  inferior  acromioclavicular.  In  reality  they  are  simply  the  thickened 
portions  of  the  capsular  ligament.  This  capsular  ligament  is  ruptured  in  the  not  infre- 
quent cases  of  lu.xation  which  occur  here.  Running  from  the  under  surface  of  the 
clavicle,   a  short  distance  from  its  outer  end,  to  the  coracoid  process  below,  is  the 


Interarticular  fibrocartilag* 


Anterior  sternoclavicular  Costocla 
Interclavicular  ligament 


rhomboid  ligament 


First  piect  of  sternum 


Fig.  235. — SternoclaMCular  ]omt  and  attachments  of  the  mner  end  of  the  clavicle. 

coracoclavicular  ligament.  It  is  composed  of  two  parts,  an  antero-external  square 
ligament  called  the  trapezoid,  and  a  postero-internal  conical  one  called  the  conoid. 

The  bone  may  be  fractured  just  external  to  these  ligaments,  giving  rise  to  a  peculiar 
deformity  to  which  attention  will  be  called  in  describing  the  fractures  of  the  clavicle. 

From  the  coracoid  process  the  coraco-acromial  ligament  runs  outward  and  up- 
ward to  the  acromion  process,  the  coracohumeral  outward  and  do\\'nward  to  the  neck 
of  the  humerus,  and  the  costocoracoid  ligament  inward  to  the  first  rib  at  its  cartilage. 

The  Shoulder-joint. — The  upper  extremity  being  an  organ  of  prehension  and 
not  of  support,  the  shoulder-joint,  which  is  the  articulation  which  connects  it  with  the 
trunk  through  the  shoulder-girdle,  is  constructed  with  the  idea  in  view  of  favoring 
and  permitting  motion,  and  not  of  supporting  weight  or  resisting  force.  Hence  we 
find  it  to  be  a  ball-and-socket  joint,  the  one  which  allows  of  the  freest  mo\-ements. 

The  glenoid  ca\'ity  is  a  shallow,  excavation,  not  a  deep  cup,  as  in  the  hip.  The 
articulating  surface  of  the  head  of  the  humerus  is  e.xtensive  but  not  so  large  as  it 
would  have  been  had  the  scapula  not  been  made  to  move  on  the  thorax.  The 
clavicle  keeps  the  joint  well  out  from  the  side  of  the  body;  hence  the  neck  of  the 
humerus  is  short.  The  movements  of  the  arm  are  so  extensive  and  free  that  we  do 
not  have  the  tuberosities  of  the  humerus  so  large  and  set  so  far  away  from  the  artic- 
ular surface  as  is  the  case  with  the  femur  and  its  trochanters. 

If  the  upper  portion  of  the  femur  was  like  the  upper  end  of  the  humerus,  the 
lower  extremity  would  be  continually  rolling  in  or  out,  making  walking  or  running 
at  least  difficult  if  not  impossible.  Thus  we  see  that  the  shape  of  the  bones  is 
dependent  on  the  character  of  their  functions. 


THE  SHOULDER-GIRDLE. 


223 


The  lip-anients  of  the  joints  are  inelastic  tissues;  lience  those  that  enter  into  the 
construction  oi  a  movable  joint  must  be  loose,  and  the  more  movable  a  joint  is,  the 
more  does  its  security  depend  not  on  its  ligaments,  but  on  its  muscles. 

The  shoulder-joint,  like  other  joints,  has  a  capsular  ligament  which  is  attached 
to  the  adjacent  bones  and  serves  to  keep  the  lubricating  synovial  fluid  applied  to  the 
articulating  surfaces.  In  certain  positions  this  ligament  may  also  serve  to  a  limited 
extent  to  keep  the  ends  of  the  bones  of  the  joint  in  contact. 

Besides  this  capsular  ligament  there  are  fibrous  bands  which  strengthen  it  at 
certain  places  as  they  pass  from  adjacent  processes  of  bone  on  one  side  of  the  joint 


Acromion  process 


Conoid  ligament 
'Trapezoid  ligament 

al  ligament 
'Coracoid  process 

Coracohumeral  ligament 
Coracobrachialis  muscle 
Short  head  of  biceps 


Long  head  of  biceps 


Pectoralis  major  muscle 


to  those  on  the  other.  The  muscles  and  their  tendons  pass  across  the  capsule  and 
sometimes  blend  with  it,  so  that  there  is  an  intimate  relation  between  the  muscles  and 
their  tendons  and  the  ligaments;  finally,  there  is  a  third  structure  called  the  glenoid 
ligament,  which  is  in  reality  a  fibrocartilage  that  serves  to  deepen  the  glenoid  cavity. 
The  capsular  ligament  is  attached  on  one  side  to  the  edge  of  the  glenoid  cavity, 
the  anatomical  neck  of  the  scapula,  and  the  rim  of  the  glenoid  ligament.  On  the 
other  side  it  is  attached  above  or  externally  to  the  anatomical  neck  of  the  humerus  just 
at  the  edge  of  the  articulating  surface,  but  on  the  lower  or  inner  surface  it  is  attached 
some  distance  below  the  articular  surface  (approximately  i  cm. )  and  then  turns 
upward  toward  the  edge  of  the  articular  cartilage.  Thus  a  fracture  through  the  ana- 
tomical neck  might  pass  outside  of  the  joint  above,  and  inside  of  it  below.  The  positions 
assumed  by  the  capsule  in  abduction  and  adduction  are  shown  in  Figs.  237  and  238. 


224 


APPLIED    ANATOMY. 

■  Spine 


Acromion  process 
Glenoid  process 


Ac"oTnior  r>"^oce^His  \ 


Joint  cavity 


Capsule 
Glenoid  process 
Long  head  of  triceps  muscle 


THE  SHOULDER-GIRDLE 


225 


The  capsular  ligament,  per  se,  has  not  much  strength.  There  are  two  openings 
in  it — one  is  for  the  long  tendon  gf  the  biceps  and  the  other  is  the  opening  of  the 
bursa  beneath  the  subscapularis  muscle.  Sometimes  there  is  a  synovial  extension 
beneath  the  supraspinatus  tendon  and  rarely,  in  old  people,  a  communication  with 
the  subacromial  bursa.  It  is  evident  that  in  case  of  suppuration  within  the  joint  the 
pus  would  tend  to  find  \'ent  first  through  these  openings. 

The  laxity  of  the  capsule  is  such  that  after  the  muscles  are  removed  the  head 
can  be  drawn  a  considerable  distance  away  from  the  glenoid  cavity.    When  the  mus- 

'  Acromi( 


Coracoclavicular  ligaments 


Coraco-acromial  ligament 


Coracoid  process 


Fig,  239. — View  of  the  left  scapula  and  outer  end  of  the  clavicle  from  in  front,  showing  the  ligaments  pass- 
ing from  the  coracoid  process  to  the  clavicle  and  acromion  process,  the  glenoid  ligament,  and  attachments  of  the 
long  heads  of  the  biceps  and  triceps  muscles. 

cles  are  paralyzed  the  weight  of  the  arm  causes  the  head  to  fall  away  and  a  depres- 
sion is  seen  beneath  the  acromion  process.  The  capsule  is  strengthened  by  two 
definite  and  separate  ligamentous  bands  called  the  coracohumeral  and  the  gleno- 
humeral  ligaments. 

The  coracohumeral  ligament  passes  from  the  root  of  the  coracoid  process  to  the 
anterior  portion  of  the  greater  tuberosity.  It  is  supposed  by  Sutton  to  be  a  regres- 
sion of  the  tendon  of  the  pectoralis  minor  muscle. 

The  glenokumeral  ligament  is  a  ribbon-like  band  seen  lying  alongside  of  the 

inner  edge  of  the  biceps  tendon  as  it  passes  through  the  interior  of  the  joint.      It 

passes  from  the  root  of  the  coracoid  process  near  the  edge  of  the  glenoid  cavity  to  a 

dimple  in  the  lesser  tuberosity  of  the  humerus.     Sutton  considers  it  a  regression  of 

15 


226 


APPLIED    ANATOMY. 


the  tendon  of  the  subclavius  muscle  and  homologous  with  the  ligamentum  teres  in 
the  hip.  It  is  also  called  the  superior  glenohumeral  ligament,  in  contradistinction 
to  some  bands  on  the  lower  anterior  part  of  the  capsule  which  are  called  by  some 
anatomists  the  middle  and  inferior  glenohumeral  ligaments.  Between  the  superior 
above  and  the  middle  and  inferior  below  is  the  opening  by  which  the  bursa  of  the 
subscapularis  muscle  communicates  with  the  joint. 

The  glenoid  ligament  is  the  wedge-  or  cup-shaped  ring  of  fibrocartilage  which 
deepens  the  glenoid  fossa.  It  is  attached  around  its  edge  to  the  rim  of  the  fossa 
and  at  its  upper  end  receives  the  long  tendon  of  the  biceps,  which  divides  and  blends 
with  it  on  each  side.  At  its  lower  part  when  it  is  attached  to  the  bone  it  blends  with 
the  anterior  edge  of  the  long  tendon  of  the  triceps. 

THE   MUSCLES   OF  THE   REGION   OF   THE   SHOULDER. 

The  shoulder  embraces  two  sets  of  muscles:  one  connects  the  shoulder-girdle 
with  the  trunk  and  the  other  the  humerus  with  the  shoulder-girdle. 

The  inner  end  of  the  clavicle  articulates  with  the  sternum  and  gives  a  bony 
support   to   the   shoulder-girdle   at   this    point.      The   rest    of   the    shoulder-girdle, 


Supraspinatus 
Infraspinat 


Outer  head  -^ 


Long  head  of  triceps 


Rhomboideus 
major 


Latissimus  dorsi 


Fig.  240. — Scapular  muscles. 

comprising  the  remainder  of  the  clavicle  and  all  of  the  scapula  and  bearing  the 
weight  of  the  whole  upper  e.xtremity,  hangs  from  and  is  supported  and  mo\-ed  by 
the  muscles  which  pass  from  it  to  the  vertebrje  posteriorly  and  to  the  skull,  hyoid 
bone,  and  ribs  anteriorly. 

Antei'iorly  the  clavicle  has  attached  to  its  upper  inner  third  the  clavicular  origin 
of  the  sternomastoid  muscle;  and  on  its  under  surface  is  the  subcla\-ius  muscle,  which 
arises  from  the  cartilage  and  anterior  end  of  the  first  rib.  These  muscles  aid  in  moving 
the  clavicle.  Running  from  the  third,  fourth,  and  fifth  ribs  to  the  coracoid  process  is 
the  pedoralis  minor  muscle ;  and  on  the  side  of  the  chest,  passing  to  the  posterior  edge 
of  the  scapula,  is  the  so'ratus  anterior  {magmis)  muscle.     It  will  be  alluded  to  again. 


THE  SHOULDER-GIRDLE.  227 

Posteriorly  is  the  trapezius  muscle  superficially,  and  beneath  are  the  omohyoid^ 
levator  scapula:,  and  the  two  rhomboid  muscles. 

The  trapezius  arises  from  the  superior  curved  line  of  the  occiput,  the  liga- 
mentum  nuchje,  and  the  spines  of  the  seven  cervical  and  all  of  the  thoracic  vertebrje. 
It  inserts  into  the  upper  surface  of  the  outer  third  of  the  clavicle,  acromion  process, 
and  spine  of  the  scapula  to  near  its  root.  Its  upper  fibres  directly  aid  in  sustaining 
the  weight  of  the  upper  extremity.  It  is  not  infrequently  paralyzed,  and  then  falling 
of  the  shoulder  is  marked.  It  also  tends  to  pull  the  scapula  backward  toward  the 
spine,  and  rotates  it. 

The  levator  scapulae  arises  from  the  transverse  processes  of  the  upper  four 
cervical  vertebrae  and  passes  downward  to  insert  into  the  posterior  edge  of  the 
scapula  between  its  upper  angle  and  the  root  of  the  spine  of  the  scapula. 

The  scapula  is  supported  largely  by  this  muscle;  hence  when  the  trapezius  is 
paralyzed,  as  occurs  in  division  of  its  motor  nerve,  the  spinal  accessory,  this  muscle 
is  utilized  in  counteracting  its  loss. 

The  rhomboid  muscles  arise  from  the  lower  part  of  the  ligamentum  nuchee 
and  the  spines  of  the  seventh  cervical  and  upper  five  thoracic  vertebrae  and  insert 
into  the  posterior  edge  of  the  lower  three-fourths  of  the  scapula. 

The  serratus  anterior  (magnus)  muscle  (Fig.  202),  lies  beneath  the  scapula 
and  arises  from  nine  slips  from  the  outer  surface  of  the  upper  eight  or  nine  ribs; 
the  second  rib  receives  two  slips.  It  passes  backward  and  upward  and  inserts  into 
the  posterior  edge  of  the  scapula  from  its  upper  to  its  lower  angle. 

The  serration  attached  to  the  si.xth  rib  is  the  one  that  reaches  farthest  forward 
on  the  side  of  the  chest. 

The  omohyoid  muscle  arises  posteriorly  from  the  upper  border  of  the 
scapula,  just  behind  the  suprascapular  notch,  and  then  runs  upward  and  forward  to 
the  under  surface  of  the  body  of  the  hyoid  bone.  It  is  a  digastric  or  two-bellied 
muscle  and  its  middle  tendon  is  attached  by  a  pulley-like  process  of  the  deep  cervical 
fascia  to  the  first  rib. 

MOVEMENTS  OF  THE  SHOULDER-GIRDLE. 

While  the  muscles  above  enumerated  comprise  all  those  directly  attached  to  the 
shoulder-girdle  and  trunk,  they  are  of  course  assisted  to  some  extent  by  the  muscles 
forming  the  axillary  folds,  viz.,  the  pectoralis  major  anteriorly  and  the  latissimus 
dorsi  and  teres  major  posteriorly. 

The  shoulder-girdle  is  elevated  by  the  upper  fibres  of  the  trapezius,  levator 
scapulae,  rhomboidei,  sternomastoid  (clavicular  origin) ,  and  omohyoid.  It  is  depressed 
by  the  lower  fibres  of  the  trapezius,  latissimus  dorsi,  lower  fibres  of  the  serratus  ante- 
rior (magnus),  pectoralis  major,  pectoralis  minor,  and  subclavius.  It  is  drawn  forward 
by  the  pectoralis  major,  minor,  subclavius,  serratus  anterior,  omohyoid,  and,  if  the 
arm  is  fixed,  by  the  teres  major  muscles.  It  is  drawn  back  by  the  trapezius,  rhomboidei, 
and  latissimus  dorsi  muscles.  Rotation  is  effected  by  a  combined  action  of  various 
parts  of  these  muscles. 

SURFACE   ANATOMY. 

On  observing  the  region  of  the  shoulder  it  is  noticed  that  it  projects  well  out 
from  the  trunk,  so  that  the  arm  hangs  free.  It  has  as  its  framework  three  bones — 
the  clavicle  and  scapula  above,  forming  the  shoulder-girdle,  and  the  humerus  below. 
They  radiate  from  the  region  of  the  joint,  the  clavicle  toward  the  front,  the  scapula 
toward  the  back,  and  the  humerus  downward,  forming  the  basis  of  the  shape  of  the 
shoulder,  which  is  modified  by  the  muscles,  fat,  and  skin. 

The  skin  and  fat  bridge  over  and  tend  to  obliterate  the  hollows  and  to  a  less 
extent  obscure  the  prominences.  This  is  more  the  case  as  applied  to  the  muscles 
than  the  bones,  hence  the  bones  form  the  better  landmarks  or  guides. 

Age  and  sex  modify  the  surface  appearances.  In  children  the  bones  are  but 
slightly  developed  and  their  prominences  not  marked.  Fat  is  usually  abundant  and  it 
is  often  no  easy  task  to  recognize  by  the  sense  of  touch  the  various  anatomical  parts 
and  determine  whether  or  not  they  have  been  injured.      For  this  reason  one  should 


228 


APPLIED    ANATOMY. 


endeavor  to  increase  his  skill  by  taking  ad\'antage  of  every  opportunity  that  offers 
for  examination.  In  the  case  of  women  the  same  thing  usually  exists,  but  to  a  less 
degree.  In  the  somewhat  emaciated  adult  male  the  structures  can  be  recognized  to 
best  advantage. 

The  clavicle  is  subcutaneous,  and  even  in  children  and  fat  people  can  be  felt 
throughout  its  entire  length.  Its  large,  knob-like  inner  e.xtremit}-  projects  consider- 
ably above  the  upper  edge  of  the  sternum,  which  can  be  felt  at  the  suprasternal  notch. 
Take  particular  notice  of  its  size  and  compare  it  with  the  one  on  the  opposite  side  so 
as  not  to  be  misled  as  to  its  being  diseased  or  luxated.  Follow  the  bone  to  its  outer 
extremity,  which  is  higher  than  the  inner,  more  so  when  lying  down  than  when 
standing.     A  prominent  ridge  marks  its  outer  extremity;  if  it  is  difficult  to  recognize-. 


Infraclavicular  triangle 
Outer  end  of  clavicle' 


Tip  of  acromion  process' 

Greater  tuberosity 

Head  of  humerus 
Deltoid  muscle 


Coracoid  process 

Lesser  tuberosity 
Pectoralis  major 


Fig.  241. — Surface  anatomy  of  the  shoulder. 

as  will  often  be  the  case,  then  continue  directly  outward  to  the  point  of  the  shoulder, 
which  is  formed  by  the  tip  of  the  acromion  process.  Having  recognized  this  point, 
the  end  of  the  clavicle  will  be  found  about  2.5  to  3  cm.  (i  to  i%m.)  directly  inward 
from  it. 

In  the  median  line  above  the  sternum  is  the  suprasternal  notch  with  the  promi- 
nent sternal  origins  of  the  sternomastoid  muscles  on  each  side.  Just  to  the  outer  edge 
of  these  tendons  lie  the  sternoclavicular  joints.  The  one  on  the  right  side  marks  the 
ending  of  the  innominate  arten,'  and  the  commencement  of  the  right  common  carotid 
and  subclavian.  That  on  the  left  marks  the  left  carotid  with  the  subclavian  directly 
to  its  outer  side  and  a  little  posteriorly. 

If  the  head  is  extended  and  turned  to  the  opposite  side  the  clavicular  origin  of 
the  sternomastoid  is  made  \'isible.      It  arises  from  the  !iii/e>-  third  of  the  bone. 


THE  SHOULDER-GIRDLE.  229 

The  inner  two-thirds  of  the  clavicle  is  convex  forward.  Above  this  portion  is 
the  subclavian  triangle  in  the  supraclavicular  fossa.  The  oute7-  third  of  the  clavicle 
is  convex  backward  and  from  its  upper  surface  the  trapezius  muscle  can  be  felt  pro- 
ceeding upward.      This  leaves  the  middle  third  of  the  bone  free  from  muscle. 

Under  the  middle  of  the  bone  passes  the  subclavian  artery.  It  curves  upward 
about  2.5  cm.  (i  in. )  above  the  clavicle  to  descend  again  to  the  sternoclavicular  joint. 
The  arch  so  formed  indicates  the  apex  of  the  lung  because  the  subclavian  artery 
rests  on  the  pleura.  The  internal  jugular  \-ein  passes  down  opposite  the  interval 
between  the  sternal  and  clavicular  heads  of  the  sternomastoid  muscle. 

Just  above  the  clavicle,  a  little  internal  to  its  middle,  and  behind  the  clavicular 
origin  of  the  sternomastoid  muscle  is  seen  the  external  jugular  vein.  It  terminates 
in  the  subclavian  vein,  which  lies  to  the  inner  (anterior)  side  of  the  artery.  To  the 
outer  side  of  the  artery  the  cords  of  the  brachial  plexus  pass  upward  and  inward. 
They  become  prominent  in  emaciated  subjects  when  the  head  is  turned  forcibly 
toward  the  opposite  side.  The  posterior  belly  of  the  omohyoid  muscle  varies  much 
in  its  position,  sometimes  it  lies  behind  the  clavicle,  at  others  two  or  three  centimetres 
above  it. 

Immediately  below  the  clavicle  is  the  infraclavicular  fossa.  At  its  inner  extremity 
can  be  felt  the  first  rib.  As  it  is  exceedingly  easy  to  mistake  the  ribs,  it  is  best,  in 
counting  them,  to  locate  the  second  rib  by  recognizing  the  angle  of  the  sternum, 
(angle  of  Ludwig)  to  which  it  is  opposite,  on  the  surface  of  the  sternum  about  5  cm. 
(2  in. )  below  its  upper  edge.  Attached  to  the  lower  edge  of  the  inner  half  of  the 
clavicle  is  the  pectoralis  major  muscle  and  to  the  outer  third  the  deltoid  muscle. 

This  leaves  one  sixth  of  the  lower  edge  of  the  cla\acle  free  from  muscular  attach- 
ments. This  forms  the  base  of  the  subclavicular  triangle  and  its  two  sides  are  formed 
by  the  adjacent  edges  of  the  pectoralis  major  and  deltoid  muscles.  Beneath  this 
triangle  runs  the  first  portion  of  the  axillary  artery  with  the  vein  to  its  inner  side 
and  the  cords  of  the  brachial  plexus  to  its  outer  side.  Deep  pressure  at  this  point 
compresses  it  against  the  second  rib. 

Just  to  the  outer  side  of  the  junction  of  the  middle  and  outer  thirds  of  the 
clavicle,  in  front  of  the  deepest  part  of  the  conca\ity  of  the  clavicle  and  about  2. 5  cm. 
( I  in. )  below  it,  is  the  coracoid  process.  It  is  better  felt  by  pressing  the  fingers  flat 
on  the  surface  than  by  digging  them  in.  It  is  somewhat  obscured  b)'  the  edge  of 
the  deltoid  muscle,  which  covers  it.  Running  from  the  coracoid  to  the  acromion 
process  is  the  sharp  edge  of  the  coraco-acromial  ligament.  An  incision  midway 
between  the  two  processes  would  open  the  joint  and  strike  the  long  biceps  tendon 
as  it  winds  over  the  head  of  the  humerus  to  reach  the  upper  edge  of  the  glenoid 
cavity. 

Beneath  the  acromion  process  is  felt  the  greater  tuberosity  of  the  humerus.  If 
the  arm  is  placed  alongside  of  the  body  with  the  palm  facing  forward,  a  distinct  groove 
can  be  felt  to  the  inner  side  of  the  acromion  process  passing  downward  on  a  line  with 
the  middle  of  the  arm.  It  is  the  bicipital  groove  for  the  long  tendon  of  the  biceps 
muscle.  The  bony  process  of  the  humerus  to  its  outer  side  is  the  greater  tuber- 
osity and  that  to  its  inner  side,  between  it  and  the  coracoid  process,  on  a  slightly 
lower  level,  is  the  lesser  tuberosity.  It  will  be  noted  that  the  greater  tuberosity  pro- 
jects beyond  the  acromion  process  and  forms  the  prominence  of  the  shoulder.  On 
rotating  the  arm  the  tuberosities  can  be  distinctly  felt  moving  under  the  deltoid  muscle. 

Following  the  acromion  process  around  toward  the  back  it  turns  abrupdy  where 
it  joins  the  spine  of  the  scapula,  forming  a  distinct  angle.  This  angle  is  quite  prom- 
inent, can  be  readily  seen  and  felt,  and  can  be  used  as  a  landmark  for  measuring  the 
length  of  the  humerus.  If  the  spine  of  the  scapula  is  followed  still  farther  it  ends 
in  its  root  at  the  posterior  border  of  the  bone  opposite  the  upper  edge  of  the  fourth 
rib  and  third  thoracic  spine.  This  marks  the  upper  extremity  of  the  fissure  of  the 
lung;  with  the  arm  to  the  side,  the  lower  angle  of  the  scapula  lies  over  the  seventh 
interspace. 

Axilla. — On  raising  the  arm  directly  out  from  the  body  the  armpit  and  axillary 
folds  become  visible.  The  rounded  edge  of  the  anterior  axillary  fold  is  formed  by 
the  pectoralis  major  muscle.  It  follows  the  fifth  rib  and  its  upper  end  merges  with 
the  lower  edge  of  the  deltoid  muscle. 


23°  APPLIED    ANATOMY. 

If  firm  pressure  is  made  along  the  inner  or  lower  edge  of  the  outer  extremity 
of  the  anterior  axillary  fold  the  upper  end  of  the  biceps  muscle  can  be  felt,  and  lying 
along  with  it,  to  its  inner  side,  is  the  swell  formed  by  the  coracobrachialis  muscle. 

Along  the  inner  edge  of  the  coracobrachialis  muscle  lies  the  axillary  artery  with 
its  vein  to  the  inner  side.  This  is  a  little  anterior  to  the  middle  of  the  axilla.  The 
artery  can  be  felt  pulsating  along  the  inner  edge  of  the  coracobrachialis  and  can  be  com- 
pressed by  pressure  made  in  an  outward  and  backward  direction  against  the  humerus. 
The  line  of  the  axillary  artery  is  from  the  middle  of  the  clavicle  down  along  the  inner 
edge  of  the  coracobrachialis  muscle,  which  will  be  anterior  to  the  middle  of  the  axilla. 

The  posterior  fold  of  the  axilla  is  formed  by  the  latissimus  dorsi  and  teres  major 
muscles.  By  deep  pressure  in  the  axilla,  posterior  to  the  vessels,  the  arm  being 
abducted,  the  rounded  head  of  the  humerus  can  be  felt. 

When  the  arm  is  brought  more  to  the  side  the  tissues  of  the  axilla  relax  and  any 
enlarged  lymph-nodes  present  may  be  recognized.     When  normal  they  cannot  be  felt. 

Winding  around  the  surgical  neck  of  the  humerus  from  behind  forward  under 
the  deltoid  muscle  about  at  the  junction  of  its  upper  and  middle  thirds  is  the  pos- 


Pectoralis  major 


Coracobrachiali! 


a  head  of  triceps  rr.uscle 
Teres  major  and  Ictissimus  dorsi  muscles 


Fig.  242. — Surface  anatomy  of  the  axilla. 

terior  circumflex  artery  and  circumflex  nerve.  Hence  a  blow  at  this  point  may  injure 
the  nerve  and  cause  paralysis  of  the  deltoid  muscle.  The  line  of  fracture  of  the 
surgical  neck  of  the  humerus  would  also  lie  at  this  point. 

DISLOCATIONS  OF  THE  CLA\TCLE. 

Dislocation  of  the  Sternal  End  of  the  Clavicle. — The  sternal  end  of  the 
clavicle  is  most  commonl}-  dislocated  forward.  Other  dislocations,  which  may  be 
upward  or  backward,  are  very  rare.  The  range  of  movement  of  the  clavicle  approxi- 
mates 60  degrees. 

The  bone  is  lowest  when  the  elbow  is  brought  forward  across  the  front  of  the  body 
and  highest  when  the  arm  is  raised  and  placed  behind  the  neck.  The  luxation  is  pro- 
duced by  the  shoulder  being  violently  depressed  and  pushed  backward,  as  in  falling 
on  it;  in  some  cases  an  inward  thrust  may  be  added.  As  the  clavicle  descends  its  under 
surface  comes  into  contact  with  the  first  rib,  which  acts  as  a  fulcrum,  and  the  inner 
extremity  is  lifted  upward  and  forward,  rupturing  the  sternoclavicular  ligaments.  The 
rhomboid  ligament  remaining  intact  prevents  a  wider  displacement  of  the  bone. 


THE  SHOULDER-GIRDLE. 


231 


As  regards  treatment,  to  reduce  the  luxation  the  shoulder  should  be  elevated 
and  drawn  outward  and  backward.  While  pressure  is  made  on  the  protruding  bone 
the  arm  is  used  as  a  lever  and  the  bone  tilted  into  place.  LTsually  reduction  can  be 
readily  accomplished,  but  most  people  have  found  it  difficult  to  retain  the  parts  in 


Fig.  243. — Dislocation  of  tiie  sternal 


nd  of  the  clavicle  upward  and  forward,  showing  how  the  first  rib  acts  ; 
fulcrum  and  the  clavicle  as  a  lever. 


place.  The  only  sure  way  of  doing  so  is  to  keep  the  patient  in  bed  on  his  back. 
Stimson,  following  Velpeau  and  Malgaigne,  advises  the  application  of  an  anterior 
figure  eight  bandage  of  plaster  of  Paris;  Hamilton  says  deformity  remains  after  any 
method  of  treatment,  but  that  function 
will  be  but  little  impaired. 

In  upward  dislocations  the  case  of 
R.  W.  Smith  has  shown  that  the  end  of 
the  bone  passes  behind  the  sternal  origin 
of  the  sternomastoid  muscle. 

In  backward  dislocations  pressure 
on  the  trachea  and  oesophagus  have 
caused  difficulty  in  breathing  and  swal- 
lowing; cyanosis  due  to  pressure  on  the 
internal  jugular  vein  has  been  observed 
in  one  case.  When  one  recalls  the 
function  of  the  clavicle  in  keeping  the 
shoulder  out  from  the  body,  it  is  readily 
seen  that  when  the  security  of  its  inner 
attachment  has  once  been  destroyed  dis- 
placement is  favored  by  the  weight  of 
the  upper  extremity  as  well  as  by  the 
action  of  all  the  muscles  which  pass 
from  the  head,  neck,  and  trunk  to  the 
shoulder-girdle  and  humerus. 

In  these  dislocations  of  the  sternal 
end  of  the  clavicle  the  fibrocartilaginous 
disk  of  the  joint   sometimes  is  carried  out  with  the  clavicle  and  sometimes  remains 
attached  to  the  sternum,  more  often  it  follows  the  clavicle. 

Dislocation  of  the  Acromial  End  of  the  Clavicle. — The  acromial  end  of 
the  clavicle  may  be  dislocated  either  upward  or  downward.  Nearly  all  the  disloca- 
tions are  upward. 

The  displacement  is  usually  produced  by  direct  violence,  a  blow  on  the  top  or 
back  of  the  shoulder  driving  the  acromion  down  and  inward.      The  clavicle  not  only 


Fig.  244. — Luxation  of  the  outer  end  of  the  clavicle 
upward,  showing  the  coracoid  process  acting  as  a  fulcrum. 
As  the  outer  end  of  the  clavicle  rises,  the  lower  angle  of  the 
scapula  is  carried  toward  the  median  line  and  the  acromion 
process  is  depressed  and  torn  loose  from  the  clavicle  above. 


232  APPLIED    ANATOMY. 

rises  but  also  goes  backward,  or  the  scapula  comes  forward,  so  that  the  end  of  the 
clavicle  ma\-  rest  on  the  acromion  process.  In  this  dislocation  the  base  of  the  cora- 
coid  process,  on  which  the  cla\icle  rests  and  to  which  it  is  bound  by  the  conoid  and 
trapezoid  ligaments,  acts  as  a  fulcrum.  The  scapula  rotates  on  an  anteroposterior 
axis,  passing  through  the  base  of  the  coracoid  process,  and  as  the  inner  portion  of 
the  bone  rises,  its  outer  portion, — that  is,  the  acromion  process, — descends  and  is  torn 
from  the  outer  end  of  the  cla\-icle. 

The  deformity  produced  by  the  upwardly  projecting  end  of  the  clavicle  is  t}'pical. 
The  luxation  may  be  complete  or  incomplete.  When  incomplete  the  injur}-  is  con- 
fined to  the  acromioclavicular  joint;  when  complete  the  conoid  and  trapezoid  ligaments 
are  partially  or  wholly  ruptured. 

The  joint  usually  possesses  a  poorly  de\eloped  fibrocartilage  and  inclines  upward 
and  outward  so  that  the  inclination  favors  the  rise  of  the  clavicle.  When  the  conoid 
and  trapezoid  ligaments  are  not  ruptured  they  sene  as  the a.xis  on  which  the  scapula 
rotates  forward  so  that  the  outer  end  of  the  cla\-icle  slips  backward  on  the  acromion 
process.  This  led  Hamilton  to  describe  these  luxations  as  back^\'ard  lu.xations.  In 
rare  instances  the  end  of  the  cla\-icle  seems  to  be  displaced  posteriorly  without 
rising  abo\'e  its  normal  level.  We  reported  one  such  case  in  the  Annals  of 
Surgeiy  se\-eral  years  ago.  Reduction  of  the  displacement  is  easily  effected,  but 
the  same  difficulty  in  keeping  the  bone  in  place  has  been  experienced  in  this  disloca- 
tion as  in  dislocations  of  the  inner  extremity.  Bandages  going  over  the  shoulder 
and  down  the  arm  and  under  the  elbow  are  commonly  employed.  The  only  sure 
way  of  keeping  the  cla\dcle  in  its  proper  position  is  to  operate  and  fasten  it  to  the 
acromion  with  wire  or  chromicised  catgut.  When  the  patient  is  put  in  bed  the  bones 
are  readily  replaced. 

DoivniLiard  dislocation  though  rare  does  seem  to  ha\-e  sometimes  occurred. 
From  the  fact  of  the  under  surface  of  the  clavicle  resting  almost  or  quite  on  the 
coracoid  process  it  is  difficult  to  see  how  it  is  possible  for  this  injury  to  take  place. 
It  must  take  place  \\-hile  the  scapula  is  violently  twisted  on  the  clavicle.  The 
displacement  is  readily  reduced  and  shows  but  little  tendency  to  recurrence. 

DISLOCATIOXS  OF  THE  SHOULDER. 

The  dislocations  of  the  shoulder  are  to  be  studied  from  the  anatomical  and  not 
from  the  clinical  standpoint.  A  knowledge  of  the  anatomical  construction  of  the 
various  parts  involved  is  to  be  applied  to  the  explanation  and  elucidation  of  the 
methods  of  production,  the  signs  and  symptoms  observed,  and  the  procedures  neces- 
sary for  reduction. 

Classification. — For  our  purpose  there  are  tivo  forms  of  dislocations  of  the 
shoulder — anterior  and  posterior.  These  tvvo  forms  are  entirely  different  and  must 
be  studied  separately. 

Ante)-ior  Dislocation. — An  anterior  luxation  is  one  in  which  the  head  of  the 
humerus  is  either  on  or  anterior  to  the  long  head  of  the  triceps  muscle  at  the  lower 
edge  of  the  glenoid  ca\ity. 

Posterior  Dislocation. — A  posterior  luxation  is  one  in  which  the  head  goes  poste- 
rior to  the  glenoid  cavit\'  and  usually  rests  beneath  the  spinous  process  of  the  scapula, 
hence  this  is  called  subspinous  dislocation. 

W'hen  the  head  is  lu.xated  anteriorly  it  may  pass  so  far  inward  as  to  rest  between 
the  coracoid  process  and  the  cla\'icle ;  hence  this  form  is  called  subclavicular. 

When  the  head  does  not  pass  so  far  inward,  but  rests  on  the  anterior  edge  of  the 
glenoid  cavity  below  the  coracoid  process,  it  is  called  a  siibcoracoid  luxaticm. 

W^hen  it  rests  on  the  anterior  and  lower  edge  of  the  glenoid  ca^'ity,  sometimes 
on  the  long  head  of  the  triceps  muscle  or  just  anterior  to  it,  it  is  called  a  subglenoid 
luxation. 

ANTERIOR  DISLOCATIOX  OF  THE  SHOULDER. 

The  head  of  the  bone  almost  alwavs  comes  out  through  the  anterior  portion  of 
the  capsule  and  slips  beneath  the  coracoid  process.  From  this  point  it  may  shift  its 
position  either  a  little  farther  inward,  when  it  is  called  a  subclavicular  luxation,  or  a 
little  farther  downward  and  outward,  when  it  receives  the  name  of  subglenoid. 


THE  SHOULDER-GIRDLE. 


233 


As  a  matter  of  fact  the  head  usually  comes  to  rest  beneath  the  coracoid  process 
and  permanent  fixation  of  the  bone  either  in  the  subclavicular  or  subglenoid  positions 
is  very  rare.  As  the  symptoms  and  methods  of  treatment  are  identical  they  will  all 
be  included  under  the  one  head  of  subcoracoid  luxations.  What  are  commonly 
regarded  as  subglenoid  lu.xations  are  really  subcoracoid. 

Method  of  Production  of  Anterior  Luxations. — Anterior  luxations  are  produced 
by  the  arm  being  hyperabducted,  rotated  outward,  and  the  head  of  the  bone  pushed 
or  pulled  in  toward  the  body.  Rotation  may  not  be  essential,  but  it  is  largely 
responsible  for  the  wide  detachment  of  the  capsule  which  is  present  in  these  injuries. 
When  the  arm  is  raised  from  the  body  much  beyond  a  right  angle  the  greater 
tuberosity  strikes  the  acromion  process.  If  the  hyperabduction  is  continued  the  acro- 
mion process  acts  as  a  fulcrum  and  the  head  of  the  bone  is  lifted  from  its  socket, 
tearing  away  the  capsule  of  the  joint  in  front  of  and  below  the  glenoid  cavity. 


Fig.  245. — Dislocation  of  the  shoulder;  action'of  the  bones;  by  extreme  abduction  of  the  humerus  over  the 
acromion  process  as  a  fulcrum  the  head  is  levered  out  of  the  socket. 


If  now  the  arm  rotates,  the  capsule  is  still  farther  detached  and  if  the  force  con- 
tinues to  act,  as  in  those  cases  in  which  a  person  is  thrown  forward  and  alights  on 
the  outstretched  arm,  or  if  the  axillary  muscles  contract,  the  head  is  thrust  from  its 
socket.  After  once  leaving  the  socket,  subsequent  movements  may  cause  the  head 
to  assume  various  positions  around  the  glenoid  cavity;  as  a  matter  of  fact  it  is  almost 
always  below  the  coracoid  process. 

Parts  Injured. — When  the  lu.xation  occurs  the  arm  is  hyperabducted  and,  owing 
to  the  acromion  process  being  somewhat  posterior  to  the  glenoid  ca\-ity,  pointing 
backward,  this  places  it  up  almost  or  quite  alongside  of  the  head.  The  force  which 
thrusts  the  bone  out  acts  downward  toward  the  axilla  and  inward  toward  the  body. 
The  posterior  border  of  the  scapula  is  prevented  from  descending  by  the  levator 
scapulae  and  rhomboid  muscles,  hence  it  is  the  joint  which  descends  and  tears  loose 
the  capsule  already  stretched  tighdy  over  the  head  of  the  humerus. 

This  is  the  reason  why  the  lower  portion  of  the  capsule  is  torn ;  it  is  the  longi- 


2  34  APPLIED    ANATOMY. 

tudinally  acting  force  that  does  it.  When  the  transverse  force  acts  it  is  expended  on  the 
anterior  portion  of  the  joint  because  the  joint  is  at  the  anterior  portion  of  the  scapula. 
Posterior  to  the  joint  the  scapula  rests  on  the  chest,  so  it  is  its  anterior  portion  which 
is  forced  inward,  thus  rupturing  the  capsule  at  this  point.  The  fulcrum,  or  acromion 
process,  is  also  posterior  to  the  midline  of  the  joint. 

By  a  combination  of  these  two  forces  (longitudinal  and  transverse)  the  capsule 
is  ruptured  at  its  lower  and  especially  its  anterior  portion.  Its  tearing  is  favored  by 
a  twisting  or  external  rotation  of  the  humerus.  The  attachment  of  the  capsule  is 
torn  from  the  rim  of  the  glenoid  cavity,  not  from  the  humerus,  and  a  fragment  of  the 
bony  rim  frequendy  comes  with  it.      The  opening  is  large  and  embraces  nearly  or 


Prominent  acromion 
process" 


Coracoid  process- 


Prominence  formed 

by  the  head  of' 

the  humerus 


Fig.  246. — Surface  view:  subcoracoid  dislocation  of  the  humerus,  showing  the  elevation  of  the  shoulder, 
abduction  of  the  arm,  prominence  of  the  displaced  head  beloiv  the  coracoid  process,  flattening  of  the  shoulder, 
and  tense  fibres  of  the  deltoid  muscle. 

quite  half  the  circumference  of  the  joint.  It  is  limited  above  by  the  coracoid  process. 
The  coracohumeral  and  superior  glenohumeral  ligaments  lying  in  front  of  the  long 
tendon  of  the  biceps  also  limit  the  tear  upwards.  If  the  tear  does  not  extend  so  high 
it  is  because  the  subscapularis  muscle,  instead  of  being  torn,  is  wedged  in  between 
the  head  and  the  coracoid  process.  Below,  the  tear  is  limited  by  the  insertion  of  the 
long  head  of  the  triceps.  As  the  head  luxates  it  cannot  pierce  the  triceps  tendon, 
so  it  slips  behind  it  in  a  posterior  luxation  and  in  front  of  it  in  an  anterior  luxation. 
The  supraspinatus,  infraspinatus,  and  teres  minor  muscles  are  all  posterior;  they 
blend  more  or  less  with  the  capsule  and  as  the  head  luxates  they  are  stretched  with 
it  over  the  glenoid  cavity. 

The  long  tendon  of  the  biceps,  while  it  may  sometimes  be  torn  loose  from  the 
bicipital  groove  after  rupture  of  the  transverse  ligament,  is  usually  so  loose  that  it 


THE  SHOULDER-GIRDLE. 


235 
The  subscapularis 


follows  the  head  without  being  detached  from  its  connections, 
muscle  not  infrequently  has  its  lower  edge  torn. 

The  brachial  ple.xus  and  blood-vessels  are  pushed  inward  by  the  head,  but  when 
the  arm  is  abducted  they  are  stretched  over  it,  running  close  to  the  coracoid  process. 


1  relation  to  each  other  and 


As  the  circumflex  nerve  winds  around  the  surgical  neck  of  the  humerus,  it  may  be 
ruptured  or  tightly  stretched  over  the  head  of  the  bone. 

Hyperabduction  stretches  the  vessels  and  nerves  so  forcibly  over  the  head  just 
prior  to  its  leaving  the  socket  as  sometimes  to  produce  serious  injury  to  them. 


Signs  and  Symptoms. 

There  is  (i)  at  first  elevation  then  lowering  of  the  shoulder,  (2)  flattening  of  the 
deltoid  muscle,  (3)  projection  of  the  elbow  away  from  the  side.  (4)  The  normal 
hollow  below  the  outer  third  of  the  clavicle  is  filled  up ;  the  head,  covered  by  the  deltoid, 
may  sometimes  even  make  a  rounded  prominence  at  this  point  which  can  frequently  be 
felt.  (5)  If  the  elbow  is  raised  and  the  hand  placed  on  the  opposite  shoulder  and  held 
there  the  elbow  cannot  be  brought  flat  on  the  chest  (Dugas's  sign),  (6)  with  the 


236  APPLIED    ANATOMY. 

arm  to  the  side  the  distance  from  the. acromion  process  to  the  external  condyle  is 
increased,  with  the  arm  abducted  to  a  right-angle,  the  same  distance  is  decreased  as 
compared  with  the  previous  position  as  well  as  when  compared  with  the  arm  of  the 
opposite  side  (see  Fig.  248). 

1 .  Lowering  the  shoulder  obviates  pain  by  relaxing  the  deltoid  and  preventing 
it  from  forcing  the  head  upward  in  its  displaced  position. 

2.  Flattening  of  the  shoulder  is  due  to  the  head  and  tuberosities  being  displaced 
inward,  thus  leaving  the  socket  empty.  A  marked  depression  can  be  felt  with  the 
fingers  below  the  prominent  acromion  process. 

3.  Projection  of  the  elbow  from  the  side  is  due  to  tension  of  the  deltoid  muscle 
because  the  head  is  lower  than  normal.  In  its  natural  position  the  top  of  the  head  is 
about  level  with  the  coracoid  process;  when  luxated  it  is  below  it. 

4.  The  normal  hollow  below  the  outer  third  of  the  clavicle  is  lost  because  here  is 
where  the  head  lies.      It  may  form  a  distinct  prominence  and  when  the  arm  is  rotated 


Fig.  248. — SubcoracoiH  dislocation  of  the  shoulder.  The  head  of  the  humerus  has  slipped  off  its  pedestal  or 
shoulder-girdle  onto  the  side  of  the  thorax.  This  shows  how  the  arm  is  shortened  and  why  it  is  necessary  to 
make  traction  in  order  to  replace  the  humerus  up  again  on  the  shoulder-girdle. 


if  the  surgeon  lays  his  hand  at  this  point  the  tuberosities  can  be  felt  to  rotate  beneath. 
If  the  arm  is  abducted  the  head  can  usually  be  felt  in  the  axilla,  where  it  may  even 
form  a  prominence. 

5.  In  Dugas's  test  the  elbow  cannot  be  brought  to  the  chest  because  the  outer 
end  of  the  humerus  is  held  close  to  the  chest-wall.  On  account  of  the  thora.x  being 
rounded  like  a  barrel  it  is  necessary  for  the  outer  end  of  the  bone  to  rise  as  the  inner 
end  falls. 

6.  The  reason  for  the  difference  in  measurements  when  the  shoulder  is  luxated 
is  readily  seen  by  the  fact  that  the  head  is  displaced  downward  and  inward  as  shown 
in  the  accompanying  figure. 

Treatment. 

Reduction  of  an  anterior  luxation  of  the  shoulder  can  be  accomplished  in  two 
ways,  viz. ,  the  direct,  in  which  the  head  is  pulled  or  pushed  back  into  the  socket, 
and  the  indirect,  in  which  it  is  levered  back. 

Direct  Method. — This  consists  in  first  placing  the  arm  in  approximately  the 
position  it  occupied  when  lu.xated  (abduction)  and  then  pulling  or  pushing  the 
head  toward  and  into  the  socket  while  the  arm  is  rotated  to  relax  the  capsule  and 
allow  the  head  to  enter.  The  usual  obstacle  to  reduction  of  a  recent  luxation  is 
muscular  contraction.  The  main  muscles  acting  are  the  deltoid,  pectoralis  major, 
latissimus  dorsi,  and  teres  major.  To  effect  reduction  the  action  of  these  muscles 
must  either  be  held  in  abeyance  or  overcome  by  force.  This  may  be  accomplished 
in  several  ways,  viz. ,  by  the  use  of  general  anjesthesia,  by  such  gentle  manipulations 


THE  SHOULDER-GIRDLE. 


237 


as  will  not  incite  the  muscles  to  contraction,  by  a  quick  movement  accomplishing  the 
object  before  the  muscles  are  able  to  contract,  or,  finally,  by  overcoming  the  muscular 
action  by  steady  continuous  traction.  General  ansesthesia  is  the  surest  way  of  obvi- 
ating muscular  contraction. 

The  question  of  muscular  contraction  having  been  solved  by  one  or  more  of  these 
expedients  the  actual  replacement  is  to  be  accomplished  by  dragging  or  pushing  the 
head  back  over  the  route  it  took  in  coming  out.  The  opening  in  the  capsule  is 
below  and  anterior,  therefore  the  arm  is  to  be  strongly  abducted,  and  traction  made 
upw-ard  and  backward.  This  drags  the  head  upward  and  backward  over  the  rim  of 
the  glenoid  cavity  into  its  socket.      If  it  does  not  enter  readily  it  is  because  of  tension 


Coracoid  process 


Aero 

Long  head  of  bieeps 
Supraspinatus 


Deltoid  detached 
from  the  clavicli 
and  turned  back 


Coracobrachialis 

and  short  head 

of  biceps 


Peetoralis  major 


Pectoralls  minor 


-Subcoracoid  dislocation  of  the  shoulder.     Dissection  1 
placed  humerus. 


:howing  the  relation  of  the  muscles  to  the  dis 


of  the  untorn  part  of  the  capsule;  this  is  to  be  remedied  by  gently  rotating  the  arm, 
when  the  proper  position  will  be  revealed  by  the  slipping  of  the  head  into  place.  Rota- 
tion in  either  direction  beyond  the  proper  point  narrows  the  tear  in  the  capsule  and 
keeps  the  head  from  entering.  Traction  is  necessary  in  order  to  replace  the  head  of 
the  humerus  on  its  pedestal  or  shoulder-girdle  from  which  it  has  fallen  onto  the  side 
of  the  chest  (see  Figs.  248  and  250). 

If  it  is  desired  to  tire  the  muscles  out,  the  plan  of  Stimson  is  best.  Place  the 
patient  in  a  canvas  hammock  and  allow  the  arm  to  hang  downward  through  a  hole 
in  the  canvas.      Fasten  a  ten-pound  weight  to  the  wrist  and  inside  of  six  minutes  the 


238  APPLIED    AXATOMY. 

weight  will  have  dragged  the  head  of  the  humerus  into  place.  This  same  object  can 
be  carried  out,  but  not  so  well,  by  having  the  patient  lie  on  the  floor  and  pulling  the 
arm  directly  upward  by  means  of  a  rope  and  pullej'.  Here  the  weight  of  the  body 
acts  as  the  counter  force. 

Other  means,  such  as  the  heel  in  the  axilla,  etc.,  may  be  found  described  in 
works  on  surger}^,  but  it  is  to  be  remembered  that  the  objects  to  be  sought  are  (i)  to 
o\'ercome  the  action  of  the  deltoid  by  abducting  the  arm,  (2)  to  overcome  the  axillary 
muscles — pectoralis  major,  latissimus  dorsi,  and  teres  major — b}'  traction,  and  (3)  to 
loosen  the  capsule  and  open  the  tear  to  its  widest  extent  by  rotation  while  the  head 
is  pushed  with  the  hand  toward  and  over  the  lower  and  anterior  edge  of  the  socket. 


Fig.  250. — Diagram  to  show  how  rotation  influences  the  size  of  the  rent  in  the  capsule.  The  square  rep- 
resents the  rent  in  the  capsule  and  the  circle  the  head  of  the  humerus.  If  the  humerus  is  rotated  too  much  in 
the  direction  of  the  arrows,  either  to  the  right  or  left,  the  opening  in  the  capsule  is  so  narrowed  as  to  obstruct 
the  passage  of  the  head. 

Indirect  Method. — The  indirect  or  lever  method  has  been  best  systematized 
by  Kocher  of  Berne,  although  Henr\'  H.  Smith,  a  former  professor  of  surger\-  in  the 
University  of  Pennsylvania,  taught  a  similar  method  previously  (see  H.  H.  Smith's 
"Surgery,"'  11  vols.,  also  Packard's  "  Minor  Surgery,"  p.  204,  and  Ashhurst's  "Sur- 
gery,"  2d  Ed.,  Phila.  1878,  p.  284).  Kochers  method  is  as  follows:  J^/rsi  Step. 
— Fle.x  the  forearm  until  it  forms  a  right  angle  with  the  arm,  then,  with  the  elbow 
touching  the  side  of  the  body,  rotate  the  arm  outward  90  degrees  until  the  forearm 
points  directly  outward  ( Fig.  251).  This  causes  the  head  of  the  bone  to  rotate  out- 
ward and  leave  the  side  of  the  chest  to  take  a  position  close  to  the  glenoid  cavity. 
Second  Step. — The  arm  being  held  in  this  position,  the  elbow  is  raised  forward  until 


Fig.  251. — Kocher's  method  of  reducing  dislocation  of  the  shoulder:  First  step — Flex  the  forearm  at  a  right 
angle  to  the  arm;  bring  the  humerus  alongside  the  chest,  the  elbow  nearly  touching  the  side,  and  rotate  outward 
as  far  as  the  arm  will  go  without  undue  force. 

it  forms  a  right  angle  or  a  little  more  with  the  long  axis  of  the  body.  This  relaxes 
the  coracobrachialis  muscle,  releases  the  lesser  tuberosity,  which  may  be  caught  against 
it,  and  allows  the  head  to  pass  outward  and  ascend  from  its  low  position  up  into  the 
o-lenoid  cavitv  (Fig.  252).  Third  Step. — Carry  the  arm  obliquely  inward,  place 
the  hand  on  the  opposite  shoulder  and  bring  the  elbow  down  to  the  surface  of  the 
chest,  the  humerus  pointing  diagonally  downward  and  inward  as  in  the  Velpeau 
position  for  fractured  clavicle  (Fig.  253!. 

The  mechanism,  as  readily  demonstrated  on  the  cadaver,  is  as  follows:  The 
head  lies  to  the  inner  side  of  the  glenoid  cavit\-  with  the  tense  posterior  portion  of 
the  capsule  passing  backward.  When  external  rotation  is  made  the  capsule  is  wound 
around  the  head  and  upper  portion  of  the  neck  and  the  head  moves  out.  In  some 
instances  the  head  will  not  onlv  move  out  but  will  likewise  move  up  and  be  drawn  at 


THE  SHOULDER-GIRDLE. 


239 


once  into  place.  Bringing  the  arm  forward  and  upward  relaxes  the  coracobrachialis 
muscle,  while  bringing  it  across  the  chest  in  the  last  step  assists  the  head  over  the 
rim  of  the  glenoid  cavity  and  restores  the  member  to  its  normal  position.  Prof. 
H.  H.  Smith  brought  the  elbow  forward  befo)-e  making  the  external  rotation  instead 
of  after,  as  did  Kocher.  This  is  probably  the  better  way  because  persistence  in  rotat- 
ing outward  when  the  lesser  tuberosity  is  caught  beneath  the  tense  coracobrachialis 
muscle  is  one  cause  of  the  frequent  fracture  of  the  humerus  in  attempting  to  carry 


Fig.  252. — Kocher's  method  of  reducing  dislocation  of  the  shoulder:  Second  step — Keeping  the  arm  in  external 
rotation,  raise  the  elbow  until  the  humerus  reaches  the  vertical  line  or  a  little  beyond. 

out  Kocher's  method;  another  cause  is  the  violent  contraction  of  the  muscles  holding 
the  upper  end  of  the  bone  immovable. 

This  method  can  be  used  without  anaesthesia,  but  it  is  at  times  e.xceedingly  pain- 
ful and  savors  of  cruelty.  It  is  particularly  applicable  for  old  and  severe  cases.  It 
depends  for  its  efficiency  on  the  integrity  of  the  posterior  portion  of  the  capsule,  if  this 
has  been  torn  loose  the  method  fails  and  the  head  simply  rotates  hi  situ.  If  this 
latter  is  the  case,  reduction  can  readily  be  effected  by  direct  traction  and  manipulation. 


353- — Kocher's  method  of  reducing  dislocation  of  the  shoulder:  Third  (final)  step — Rotate  the  arm  inward 
nd  place  the  hand  on  the  opposite  shoulder  bringing  the  elbow  down  on  the  anterior  surface  of  the  chest. 


POSTERIOR  DISLOCATIONS  OF  THE  SHOULDER. 

Posterior  dislocations  are  always  beneath  some  portion  of  the  spine  of  the  scapula, 
hence  they  have  been  called  sjibspmous.  When  the  head  lies  anteriorly  under  the 
posterior  portion  of  the  acromion  process  they  have  been  called  subacromial. 

Posterior  luxations  are  rare.  They  occur  either  when  the  arm  is  abducted  with 
strong  internal  rotation  or  by  cUrect  violence,  such  as  a  blow  on  the  anterior  portion  of 
the  shoulder,  which  forces  the  head  out  of  its  socket  backward.  The  posterior  portion 
of  the  capsule  is  torn  and  the  head  lies  posterior  to  the  glenoid  cavitv  with  its  anatomi- 
cal neck  resting  on  the  rim  and  the  lesser  tuberosity  in  the  glenoid  fossa.  The  arm 
is  inverted  and  abduction  and  rotation  impaired.  The  capsule  is  ruptured  by  internal 
rotation  while  the  arm  is  in  a  position  of  abduction,  and  then  a  push  sends  the  head  pos- 
teriorly.    We  have  seen  it  as  a  congenital  affection  resulting  from  injury  in  childbirth. 


240 


APPLIED    ANATOMY. 


Lesser  tuberosity  of  the  humerus 
Relaxed  tendon  of  coracobrachialis 
and  short  head  of  biceps 

Fig.  254.— Raising  the  arm  to  a  vertical  line  or  a  little   more   relaxe-!  thp   tpr,rlr,„   „f  n,„  t,       ,  •   ,■ 

t?^  rs^?o^!?XlS^o^'pt?erefaVdtn^tTp*SS/ 


.  Pig    2SS-— Posterior  luxation  of  the  shoulder.    The  head  of  the 
Ashhufst"]'  ''"""'^  ^"'"■'  "^^  ^™  '^  '°'^'"^  '"™^^-     (F™"i  a  Photogmph-of' 


,  prominence  beneath  tne 
s  patient  by  Dr.  A.  P.  C. 


THE  SHOULDER-GIRDLE.  241 

The  infraspinatus,  teres  minor,  and  sometimes  the  subscapularis  muscles  are 
ruptured  and  frequently  there  are  accompanying  fractures  of  the  tuberosities  or  some 
part  of  the  scapula.  The  head  makes  a  prominence  posteriorly  and  the  arm  hangs  to 
the  side  and  in  a  position  of  inward  rotation.  Reduction,  if  the  injury  is  recent,  is 
likely  to  be  easily  effected  by  pushing  the  head  directly  forward  into  its  socket. 

FRACTURES   OF    THE    SHOULDER-GIRDLE   AND    UPPER    END 
OF    THE    HUMERUS. 

FRACTURES   OF  THE   CLAVICLE. 

Fractures  of  the  clavicle  divide  with  those  of  the  radius  the  distinction  of  being 
the  most  frequent  of  any  in  the  body. 

The  clavicle  is  most  often  broken  in  its  middle  third,  next  in  its  outer,  and,  lastly, 
in  its  inner  third. 

Fracture  of  the  Inner  Third  of  the  Clavicle. — This  is  the  rarest  frac- 
ture of  the  clavicle  and  has  its  main  anatomical  interest  in  relation  to  the  costoclavic- 
ular ligament.  This  ligament  runs  obliquely  upward  and  outward  from  the  upper 
surface  of  the  cartilage  of  the  first  rib  to  the  lower  surface  of  the  clavicle,  a  distance 
of  2  cm.  (i  in.  ). 

Immediately  in  front  of  the  outer  portion  of  this  ligament  is  the  insertion  of  the 
tendon  of  the  subcla\'ius  muscle.  The  line  of  the  fracture  may  be  either  transverse 
or  oblique;  if  oblique  it  follows  the  same  direction  as  do  the  fractures  of  the  middle 
third  of  the  bone,  viz. ,  from  above,  downward  and  inward.  The  displacement  of 
the  inner  fragment  is  upward  and  of  the  outer  fragment  downward.      The  displace- 


icle  just  outside  of  the  middle,  with  the  customary  defer 


ment  of  the  inner  fragment  upward  is  promoted  by  the  attachment  of  the  clavicular 
origin  of  the  sternomastoid  muscle:  it  is  opposed  by  the  costoclavicular  (rhomboid) 
ligament  and  to  a  less  extent  by  the  subclavius  muscle. 

Fracture  of  the  Middle  Third  of  the  Clavicle. — The  clavicle  is  most 
frequently  broken  in  the  outer  half  of  its  middle  third.  The  bone  at  this  part  is  most 
slender;  it  is  here  that  the  anterior  curve  passes  into  the  posterior;  and,  finally,  it  has 
fewer  muscular  attachments  at  this  situation.  The  upper  surface  has  arising  from  its 
inner  third  the  clavicular  origin  of  the  sternomastoid  muscle.  Its  middle  third  has 
no  muscular  attachments,  and  on  its  outer  third  is  the  trapezius  muscle.  On  the 
lower  or  anterior  surface  on  its  inner  half  is  the  clavicular  origin  of  the  pectoralis 
major  and  on  its  outer  third  is  the  deltoid.  This  leaves  the  outer  half  of  the  middle 
third  free  from  muscular  attachments,  with  the  exception  of  the  subclavius  on  its 
under  surface.      It  is  through  this  part  of  the  bone  that  fractures  occur. 

Sometimes  in  children  the  line  of  fracture  is  transverse,  but  most  often  it  is 
oblique  and  always  in  the  direction  from  above  downward  and  inward. 

The  displacement  of  the  inner  fragment  is  upward,  and  of  the  outer  fragment 
downward  and  inward.  This  produces  the  deformity  seen  in  Fig.  256.  The  inner 
fragment  is  pulled  up  by  the  clavicular  origin  of  the  sternomastoid  muscle.  The 
support  of  the  clavicle  being  gone,  the  shoulder  falls  down  and  in.  It  is  impelled  in 
that  direction,  first,  by  the  weight  of  the  upper  extremity,  and,  secondly,  by  the  action 
of  the  axillary  fold  muscles, — pectoralis  major  and  minor  anteriorly  and  teres  major 
and  latissimus  dorsi  posteriorly,  and  by  the  subclavius  to  some  extent.  The  anterior 
edge  of  the  scapula  rotates  inward  and  its  posterior  edge  tilts  outward. 

In  this  manner  overlapping  is  produced,  and  measurements  of  the  injured  and 
healthy  sides  taken  from  the  sternoclavicular  to  the  acromioclavicular  joint  will 
show  some  shortening  on  the  injured  side.  As  the  continuity  of  the  shoulder-girdle 
16 


242 


APPLIED    ANATOMY. 


has  been  destroyed  and  its  prop-like  action  lost,  its  function  of  abduction  ceases,  and 
the  patient  is  unable  properly  to  elevate  the  arm.  Sometimes  the  brachial  plexus  or 
subclavian  vessels  are  injured  by  the  inner  end  of  the  outer  fragment.  The  artery 
passes  beneath  the  middle  of  the  bone,  the  vein  being  to  its   inner  side  and  the 


Brachial  plexus 
Subclavian  vessels 


Pectoralis  minor 


Pectoralis  major 


Fig.  257. — Fracture  of  the  clavicle  just  outside  the  middle.  The  outer  fragment  is  displaced  downward  and 
inward  and  the  inner  fragment  upward.  The  brachial  plexus  and  subclavian. vessels  are  behind  the  inner  end  of 
the  outer  fragment. 

brachial  plexus  to  its  outer  side.  We  have  operated  on  one  such  case  of  injury  to 
the  brachial  plexus;  and  cases  of  hsematoma  arising  from  injury  to  the  veins  and 
aneurism  from  injury  to  the  artery  have  been  recorded. 

Treatment. — When  the  line  of  fracture  is  oblique  and  in  an  adult,  healing  with  a 
certain,  often  considerable,  amount  of  deformity  is  almost  constant,  the  only  efficient 


Fig.  258. — Showing  how  the  shoulder  falls  inward  and  the  posterior  edge  of  the  scapula  tilts  outward  when  the 
prop-like  action  of  the  clavicle  is  destroyed  by  fracture. 

way  of  combating  its  occurrence  is  to  place  the  patient  in  bed  on  his  back.  This  is  the 
best  way  of  removing  the  weight  of  the  arm,  of  quieting  the  muscles,  and  by  pressure 
of  the  scapula  close  to  the  thorax  of  levering  the  shoulder  out  (see  Fig.  258). 


THE  SHOULDER-GIRDLE. 


243 


Fracture  of  the  Outer  Third  of  the  Clavicle. — Attached  to  the  outer  third 
of  the  clavicle  on  its  under  surface,  extending  not  quite  to  its  end,  are  the  coraco- 
clavicular  (conoid  and  trapezoid j  ligaments.  The  conoid  inserts  into  the  conoid 
tubercle  near  the  posterior  edge  of  the  clavicle,  while  the  trapezoid  is  broader  and 
passes  from  the  conoid  tubercle  outward  and  anteriorly  not  quite  to  the  extremity 
of  the  bone  (see  Fig.  267).  The  bone  may  be  fractured  either  through  the  part  to 
which  the  conoid  and  trapezoid  ligaments  are  attached,  or  between  them  and  the  end 
of  the  bone,  a  distance  of  about  2  cm.  (i  in.).  The  line  of  the  fracture  is  either 
transverse  or  inclines  backward  and  outward  (see  Fig.  259). 

The  displacement  of  the  outer  fragment  is  downward  and  inward.  If  the  fracture 
is  through  the  ligaments  the  displacement  is  not  marked.  If  beyond  the  ligaments, 
the  shoulder  drops,  carrying  down  the  outer  fragment,  and  the  inner  fragment  may 
be  elevated  slighdy  above  the  outer  one,  but  the  up-and-down  displacement  is  not 


Pectoralis  minor 


Pectoralis  major 


Fig.  2sg. — Fractu 


Latissimus  dorsi 


s  of  the  outer  end  of  the  clavicle 
latissimus  dors 


Teres  major 

The  outer  fragment  is  drs 
,  and  teres  major  muscles. 


1  inward  by  the  pectoralis  major 


conspicuous.  In  many  cases  the  anteroposterior  displacement  is  very  marked  and 
peculiar.  _  The  outer  fragment  is  bent  sharply  inward  at  the  site  of  fracture,  producing 
a  deformity  which  is  pathognomonic.  It  is  caused  by  the  curved  shape  of  the  bone  at 
this  point,  by  the  weight  of  the  arm,  and  by  the  action  of  the  muscles  passing  from 
the  shoulder  to  the  trunk,  especially  the  pectoralis  major  (see  Fig.  259). 

Treatment. — As  the  deformity  is  not  very  marked  any  of  the  usual  bandages, 
such  as  those  of  Velpeau,  Desault,  or  posterior  figure  eight  are  fairly  satisfactory. 

FRACTURES  OF  THE  SCAPULA. 

While  fractures  of  the  scapula  are  not  common,  there  are  a  fevv  anatomical  facts 
in  reference  to  the  scapula  and  its  muscles  which  are  worth  calling  attention  to. 

The  scapula  is  liable  to  be  fractured  more  or  less  transversely  through  the  body 
below  the  spine;  the  acromion  and  coracoid  processes  have  been  broken;  it  has  also 
been  fractured  through  the  surgical  neck,  and  the  glenoid  process  has  been  chipped  off. 


244  APPLIED    ANATOMY. 

Fracture  Through  the  Body. — The  scapula  has  attached  to  its  under  surface 
the  subscapularis  muscle,  along  its  posterior  border  is  the  serratus  anterior  (magnus) 
and  rhomboids,  to  its  dorsum  and  edge  below  the  spine  are  attached  the  infraspina- 
tus, teres  minor,  and  teres  major  muscles.  These  are  covered  by  a  strong,  tough 
fascia  which  dips  between  them  to  be  attached  to  the  bone. 

Bearing  these  facts  in  mind  it  is  readily  appreciated  why  in  many  of  these 
fractures,  which  usually  tra\'erse  the  bone  below  its  spine  from  the  a.xillary  to  the 
vertebral  border,  the  displacement  is  slight,  and  why  healing  occurs  with  some 
appreciable  deformity  but  \\  ith  littie  disabilit}-. 

If,  however,  the  fracture  is  low  down,  breaking  off  the  lower  angle,  then  the  teres 
major  and  lower  portion  of  the  serratus  anterior  (magnus )  muscles  displace  the  frag- 
ment toward  the  a.xilla,  and  this  is  to  be  borne  in  mind  in  treating  the  injury. 

Fracture  of  the  acromion  process  is  more  rare  than  would  be  e.xpected. 
It  is  the  result  of  direct  violence,  and  the  displacement  and  disability  resulting  from 
the  injury  are  slight.  The  acromion  is  covered  by  a  dense  fibrous  expansion  from 
the  trapezius  above  and  the  deltoid  below,  and  these  pre\-ent  a  wide  separation  of 
the  fragments. 

Fracture  of  the  coracoid  process  is  also  rare  and  may  occur  from  muscular 
contraction  or  direct  violence,  as  in  luxation  of  the  shoulder.  It  might  be  thought 
that  owing  to  the  action  of  the  pectoralis  minor,  coracobrachialis,  and  short  head  of 
the  biceps  muscles,  which  are  attached  to  it,  it  would  be  widely  displaced,  but  this 
is  not  so,  for  the  conoid  and  trapezoid  ligaments  still  hold  it  in  place. 

Fractures  through  the  surgical  neck  are  not  common.  They  pass  down 
through  the  suprascapular  notch  and  across  the  glenoid  process  or  head,  in  front  of  the 
base  of  the  spine  and  behind  and  parallel  with  the  glenoid  fossa.  The  tendency  of 
the  outer  fragment  to  be  dragged  down  by  the  weight  of  the  arm  is  resisted  by  the 
coraco-acromial  and  coracoclavicular  (conoid  and  trapezoid)  ligaments  as  well  as  by 
the  inferior  trans\'erse  ligament,  which  runs  from  one  fragment  to  the  other  from 
the  base  of  the  spine,  on  the  posterior  surface,  to  the  edge  of  the  glenoid  cavity. 
These  ligaments  all  remain  intact. 

Fracture  through  the  glenoid  process,  chipping  off  a  greater  or  less  por- 
tion of  the  articular  surface,  is  rarely  diagnosed.  It  occurs  sometimes  in  cases  of 
lu.xadon.  The  long  head  of  the  triceps  muscle  may  be  fastened  to  the  detached  frag- 
ment and  is  liable  to  pull  it  downward  and  therefore  some  interference  with  the  func- 
tions of  the  joint  would  be  apt  to  remain  and  prevent  complete  recovery. 

FRACTURES   OF  THE  UPPER   END   OF  THE   HUMERUS. 

Fractures  of  the  upper  end  of  the  humerus  may  occur  through  the  anatomical 
neck,  through  the  tuberosities,  detaching  one  or  both,  and  through  the  surgical  neck 
just  below  the  tuberosities.  These  fractures  are  frequently  associated  with  luxation 
of  the  head  of  the  bone. 

Fracture  through  the  Anatomical  Neck. — This  occurs  as  the  result  of  direct 
violence  and  most  often,  though  not  always,  in  old  people.  The  line  of  fracture  does 
not  always  follow  exactly  the  line  of  the  anatomical  neck,  but  may  embrace  a  portion 
of  the  tuberosities.  The  fracture  may  or  mav  not  be  an  entirely  intracapsular  one. 
The  capsule  in  its  upper  or  outer  portion  is  thickened  at  its  humeral  end  by  more  or 
less  blending  with  the  tendons  of  the  muscles  which  pass  over  it.  The  capsule  at  this 
point  is  attached  to  the  anatomical  neck  almost  or  quite  up  to  the  articular  surface. 
On  the  under  side  to  the  contrary  it  passes  about  a  centimetre  below  the  articular 
surface  and  doubles  back  to  be  attached  somewhat  closer  to  it  (see  Fig.  266,  page  253). 

In  consequence  of  this  arrangement,  a  fracture  which  follows  the  anatomical  neck 
would  be  within  the  joint  below  and  just  outside  of  it  above.  As  a  matter  of  fact, 
some  of  these  fractures  are  intra-  and  some  partly  extracapsular.  This  influences  the 
amount  and  character  of  the  displacement  and  the  course  of  healing.  If  the  fracture 
is  entirely  intracapsular,  bony  union  may  not  occur,  as  no  callus  may  be  thrown  out 
by  the  upper  fragment  and  atrophy  of  the  fragment  may  ensue.  The  fragment  is 
apt  to  be  much  displaced,  being  tilted  and  lying  to  the  inner  side  anteriorly. 
Sometimes  it  is  entirely  extruded  from  the  joint.  In  one  case  we  have  seen  it  lodged 
in  front  under  the  anterior  axillary  fold. 


THE  SHOULDER-GIRDLE. 


245 


The  signs  and  symptoms  will  vary  much,  according  to  the  position  of  the  head, 
and  a  positive  diagnosis  may  be  impossible.  A  thorough  knowledge  of  the  surface 
anatomy  is  essential  in  these  cases  and  a  careful  comparison  should  be  made  with  the 
opposite  healthy  shoulder.  Impaction  sometimes  occurs,  and  is  said  to  be  most 
often  of  the  upper  fragment  into  the  lower,  sometimes  splitting  it  and  detaching  to  a 
certain  extent  one  of  the  tuberosities.  Sometimes  it  is  the  lower  fragment  which  is 
impacted  into  the  up])er. 

Fractures  through  the  Tuberosities. — Like  the  former  these  are  often 
accompanied  by  luxation,  especially  if  one  or  both  of  the  tuberosities  is  detached. 
These  fractures  are  frequently  blended  with  fracture  through  the  anatomical  neck.  In 
this  fracture,  however,  the  influence  of  the  muscles  is  to  be  remembered.  The  supra- 
spinatus,  infraspinatus,  and  teres  minor  insert  into  the  greater  tuberosity,  and  the  sub- 
scapularis  into  the  lesser.  The  line  of  fracture  may  pass 
through  their  insertions  and  the  displacement  may  be  slight. 

The  upper  fragment  is,  however,  liable  to  be  tilted  out- 
ward by  the  contraction  of  the  supraspinatus  muscle,  w^hich 
is  attached  to  the  upper  portion  of  the  upper  fragment,  while 
there  is  no  muscle  attached  below  to  counteract  it.  In  this 
case  the  shaft  of  the  humerus  is  drawn  up  and  out  by  the 
deltoid  and  is  felt  beneath  the  acromion  process.  There  is 
but  little  rotatory  displacement  of  the  upper  fragment  because 
the  subscapularis  anteriorly  is  neutralized  by  the  infraspinatus 
and  teres  minor  posteriorly. 

In  those  instances  in  which  there  is  not  much  displace- 
ment of  the  upper  fragment,  the  lower  one  may  be  drawn 
inward  and  forward  by  the  action  of  the  muscles  of  the  ax- 
illary folds. 

Fractures  detaching  the  tuberosities  are  almost  always 
accompanied  by  luxation.  If  the  greater  tuberosity  alone  is 
detached,  it  is  drawn  up  beneath  the  acromion  by  the  supra- 
spinatus. 

In  all  these  fractures  the  subsequent  disability  is  often 
great  and  the  prognosis  is  unfavorable.  They  are  amongst 
the  hardest  in  the  body  to  correctly  diagnose.     They  are 

treated  sometimes  with  a  shoulder-cap  and  sometimes  with  the  arm  in  the  abducted 
position  while  the  patient  is  kept  in  bed.  Epiphyseal  separation  will  be  alluded  to 
farther  on. 

Fractures  of  the  Surgical  Neck. — These  are  the  most  common  fractures 
of  the  humerus.  The  surgical  neck  of  the  humerus  is  usually  defined  as  the  portion 
between  the  lower  part  of  the  tuberosities  and  the  upper  edge  of  the  tendons  of  the 
pectoralis  major  and  latissimus  dorsi  muscles.  Often,  however,  the  tendons  of  these 
.  two  muscles  continue  almost  or  quite  up  to  the  tuberosities,  hence  there  is  little  or 
no  interval  here  and  the  line  of  fracture  then  passes  through  the  upper  part  of  these 
tendons. 

The  fractures  occur  both  from  direct  and  indirect  violence  and  the  direction  of 
the  force  has  probably  something  to  do  with  the  displacement  of  the  fragments. 

Displacement. — It  can  readily  be  seen  that  if  a  blow  is  received  on  the  humerus 
below  the  tuberosities  while  the  arm  is  in  a  somewhat  abducted  position  the  head  will 
be  supported  by  the  glenoid  process  (head)  of  the  scapula  and  the  bone  will  be 
fractured  through  the  surgical  neck  and  driven  in  towards  the  body,  and,  as  the 
scapula  is  supported  posteriorly,  the  movable  lower  fragment  is  displaced  anteriorly. 
After  the  fracture  has  occurred,  and  possibly  in  some  cases  aided  by  the  peculiar 
direction  of  the  fracturing  force,  the  lower  fragment  is  drawn  upward  by  the  muscles 
running  from  one  side  of  the  fracture  to  the  other.  These  are  the  deltoid,  biceps, 
coracobrachialis,  and  the  long  head  of  the  triceps.  The  typical  displacement  is 
for  the  upper  fragment  to  be  abducted  and  some  say  rotated  out — this  latter  is  not 
without  doubt.  The  lower  fragment  is  certainly  in  front  and  to  the  inside  of  its 
normal  position. 

The  abduction  of  the  upper  fragment  is  due  to  the  unresisted  action  of  the  supra- 
spinatus muscle.     The  subscapularis  in  front  and  the  teres  minor  and  infraspinatus 


246 


APPLIED    ANATOMY, 


behind  nearly  or  quite  balance  each  other,  thus  causing  little  or  no  lateral  displace- 
ment. The  displacement  inward  and  anteriorly  of  the  lower  fragment,  is  due  to  the 
action  of  the  violence  as  already  detailed  and  is  aided  by  the  action  of  the  pectoralis 
major,  the  teres  major,  and  latissimus  dorsi  muscles,  all  of  which  pass  from  the  lower 
fragment  just  below  the  seat  of  fracture  inward  to  the  trunk. 

The  longitudinal  displacement  is  peculiar.  As  the  lower  fragment  is  drawn  up 
its  upper  end  may  be  felt  through  the  deltoid  muscle  below  and  toward  the  inner  side 
of  the  acromion.  While  the  displacement  in  most  cases  is  not  marked,  in  some  the 
lower  fragment  can  readily  be  felt  in  the  axilla  (Fig.  261  ). 

Sometimes  instead  of  the  lower  fragment  being  displaced  inward  it  goes  outward. 
In  this  case  as  it  rises  it  pushes  the  head  and  tilts  it  inward  while  it  passes  farther 
outward. 

The  diagnosis  is  to  be  made  by  a  careful  examination  and  comparison  with  the 
opposite  healthy  member.      The  head   is  recognized   to   be   in  the  glenoid  cavity, 


process 
Snprnsyj'in.iLus  muscle 


Deltoid  muscle 


Pectoralis 
major 


Pectoralis  major 


Fig.  261.— I 
spinatus,  while 
muscles  and  the 


:ure  of  the  surgical  neck  of  the  humerus.  The  upper  fragment  is  held  out  by  the  supra- 
lower  fragment  is  drawn  in  by  the  pectoralis  major,  latissimus  dorsi,  and  teres  major 
I  abducted  by  the  deltoid. 


crepitus  is  felt,  the  upper  end  of  the  lower  fragment  can  often  be  palpated,  and  on 
rotating  the  arm  the  head  of  the  bone  is  found  to  lie  stationary. 

Treatment. — The  ideal  treatment  is  extension  with  the  patient  in  bed  and  the 
arm  abducted.  As  the  upper  fragment  cannot  be  brought  in,  an  effort  may  be 
made  to  bring  the  lower  one  out.  As  these  are  usually  treated  as  walking  cases  a 
common  dressing  employed  is  a  shoulder-cap  with  the  arm  bound  to  the  side;  some- 
times an  axillary  pad  is  used  to  keep  the  arm  away  from  the  body.  In  cases  of 
fracture  associated  with  luxation  of  the  head  of  the  bone,  replacement  can  sometimes 
be  effected  by  traction  in  the  abducted  position  and  pressure  on  the  head,  general 
ansesthesia  being  used  (see  description  of  direct  method  of  reduction  under  dis- 
location of  the  shoulder,  page  236). 


THE  SHOULDER-GIRDLE. 


247 


To  aid  in  the  reduction  McBurney  devised  a  hook  which  he  inserts  into  the  upper 
fragment,  pulling  it  toward  the  glenoid  cavity. 

EPIPHYSEAL  SEPARATIONS. 

The  epiphyses  that  are  liable  to  separation  are  those  of  the  coracoid  process, 
the  acromion  process,  and  the  upper  end  of  the  humerus. 

Separation  of  the  Coracoid  Epiphysis. — The  coracoid  process  has  three 
separate  centres  of  ossification  which  fuse  with  the  body  of  the  bone  from  the  fifteenth 
to  the  twentieth  year.  Therefore  displacements  occurring  before  the  latter  age  may 
be  separations  of  the  epiphysis  and  not  true  fractures,  particularly  if  the  line  of  sepa- 
ration runs  through  the  base  of  the  coracoid. 

Separation  of  the  Acromion  Epiphysis. — The  acromion  process  is  cartilag- 
inous up  to  the  fifteenth  year.  Then  two  centres  appear  and  the  epiphysis  unites 
with  the  rest  of  the  spine  of  the  scapula  about  the  twentieth  year  or  later.  The  epi- 
physeal line  runs  posterior  to  the  acromioclavicular  joint,  just  behind  the  angle  of  the 
spine  of  the  scapula.  It  has  been  suggested  that  many  cases  diagnosed  as  sprains  and 
contusions  of  the  shoulder  are  really  epiphyseal  separations  of  the  acromion  process. 

Separation  of  the  Epiphysis  of  the  Upper  End  of  the  Humerus. — The 
upper  end  of  the  humerus  has  three  centres  of  ossifica- 
tion, one  for  the  head  and  one  each  for  the  greater  and 
lesser  tuberosities.  These  three  centres  are  blended  by 
the  seventh  year,  and  the  whole  epiphysis  unites  with  the 
shaft  at  about  the  age  of  twenty-five  years. 

The  epiphyseal  line  follows  the  lower  half  of  the 
anatomical  neck  and  then  passes  outward  to  the  insertion 
of  the  teres  minor  muscle.  This  brings  the  outer  end  of 
the  epiphyseal  line  some  distance  away  from  the  joint, 
while  the  inner  portion  of  the  line  is  within  the  joint. 
Disease  of  this  region  may  therefore  follow  the  epiphyseal 
cartilage  into  the  joint.  A  separation  of  the  epiphysis 
from  injury  will  implicate  the  joint. 

The  surgical  neck  of  the  humerus  lies  a  short  dis- 
tance below  the  epiphyseal  line  and  farther  away  on  the 
outer  side  than  on  the  inner.  The  line  of  the  epiphysis 
rises  higher  in  the  centre  of  the  bone  than  on  the  sur- 
face, making  a  sort  of  cap  for  the  end  of  the  diaphysis. 
The  symptoms  of  epiphyseal  separation  are  almost 
exactly  the  same  as  those  of  fracture  of  the  surgical  neck 
(see  page  245). 

The  supraspinatus  is  the  main  agent  in  tilting  the 
upper  fragment  outward,  while  the  muscles  inserted  into 
the  bicipital  ridges, — the  pectoralis  major  into  the  outer 
ridge  and  the  latissimus  dorsi  and  teres  major  into  the 
inner, — draw  the  lower  fragment  inward.  The  relative 
position  of  the  fragments  when  the  lower  is  displaced  outward  is  seen  in  Fig.  262 


62. — Detachment  of  the 
of  the  upper  end  of  the 


AMPUTATIONS  AND  RESECTIONS  OF  THE  SHOULDER. 
AMPUTATION  AT  THE  SHOULDER-JOINT. 

The  many  different  methods  of  amputating  at  the  shoulder  may  for  our  purposes 
be  divided  into  two  classes, — the  flap  method  and  the  racket  method. 

The  Flap  Method. — One  large  flap  may  be  made  to  the  outer  side  and  a 
short  one  to  the  inner  side  fDupuytren)  or  they  may  be  made  anteroposteriorly 
(Lisfranc).  The  flap  operations  were  done  with  long  knives  by  transfi.xion,  as  they 
originated  before  the  discovery  of  general  anaesthesia  and  by  them  the  member  was 
removed  with  great  rapidity  (Fig.  263). 

In  Dupuytre7i^  s  method  the  arm  was  raised  to  a  right  angle  with  the  body  and  the 
deltoid  muscle  grasped  with  one  hand  while  the  knife  was  inserted  beneath  it,  entering 


248  APPLIED    ANATOMY. 

just  below  the  posterior  portion  of  the  acromion  process  (its  angle)  then  passing 
under  the  acromion  to  emerge  in  front  at  the  coracoid  process.  This  flap  was  turned 
up,  the  capsule  and  muscles  divided,  the  bone  turned  out,  and  while  an  assistant 
compressed  the  remaining  tissues  they  were  divided  transversely. 

Lisfrand  s  method  consisted  in  transfixing  the  posterior  axillary  fold  from  below 
upward,  entering  the  knife  in  front  of  the  tendons  of  the  latissimus  dorsi  and  teres 
major  muscles  and  bringing  it  out  a  littie  in  front  of  the  acromion.  The  joint 
was  opened  posteriorly,  the  bone  luxated,  and  an  anterior  flap  cut  from  within  out- 
ward. Sir  William  Fergusson,  probably  the  most  skilful  operator  of  his  day,  was 
partial  to  this  operation. 

The   Racket   Method. — In  this  method  the  incision  resembles  in  shape  the 


Musculocutaneous 

1  nerve 
Internal  cutaneous  nerve 


Fig.  263. — Amputation  of  the  shoulder  by  anteroposterior  flaps.     The  upper  extremity  of   the  incision  passes 
between  the  coracoid  and  acromion  processes.     The  posterior  flap  is  the  larger. 


ordinary  racket,  such  as  is  used  in  tennis.  The  loop  encircles  the  arm,  while  the 
handle  begins  above  at  the  point  of  the  shoulder. 

There  are  two  operations  by  the  racket  method,  which  differ  as  to  the  position 
from  which  the  upper  portion  of  the  incision  starts. 

Larrcy  s  Method. — The  operation  usually  ascribed  to  Larrey  consists  in  starting 
the  incision  at  the  anterior  end  of  the  acromion  process  and  continuing  it  straight 
down  the  arm  for  three  centimetres  {1%  in.).  It  then  parts,  one  branch  sweeping 
gradually  in  a  curved  line  to  the  anterior  axillary  fold  and  the  other  to  the  posterior 
axillary  fold,  an  incision,  through  the  skin  only,  passes  across  the  inner  surface  of  the 
arm  joining  the  two  branches.  The  flaps  having  been  turned  anteriorly  and  poste- 
riorly, the  joint  is  opened  by  cutting  on  the  head  of  the  bone,  first  posteriorly,  then 
above,  and  then  anteriorly.  Tilting  the  head  outward  the  inferior  portion  of  the 
capsule  is  divided  and  the  bone  loosened  from  the  soft  parts.  These  are  com- 
pressed by  the  fingers   of  an  assistant  and  cut. 


THE  SHOULDER-GIRDLE.  249 

Spence' s  Method. — A  modification  of  Larrey's  procedure,  attributed  to  Spence 
by  the  British  and  to  S.  Fleury  by  the  French,  consists  in  commencing  the  incision 
just  outside  of  the  coracoid  process  in  the  interval  between  it  and  the  acromion 
process.  This  modification  is  probably  the  best  form  of  procedure  for  this  locality 
and  is  the  one  which  will  be  discussed  here.  It  will  be  noticed,  however,  that  it 
practically  changes  the  operation  of  I-arrey  from  one  with  anteroposterior  flaps  to  one 
with  a  single  external  flap,  as  in  the  method  of  Dupuytren.     (Fig.  263). 

The  incision  begins  just  below  the  coraco-acromial  ligament  and  lies  deep  in  the 
hollow  formed  by  the  anterior  concave  surface  of  the  outer  third  of  the  clavicle.  It 
divides  the  fibres  of  the  deltoid  muscle  longitudinally  a  short  distance  from  its  anterior 
edge.  It  will  be  recalled  that  the  deltoid  muscle  covers  the  coracoid  process  and 
extends  just  to  its  inner  side  to  be  attached  to  the  outer  third  of  the  lower  surface 
of  the  clavicle.  Between  it  and  the  adjoining  edge  of  the  pectoralis  major  muscle 
runs  the  cephalic  vein.  This  passes  downward  and  outward  along  the  inner  edge 
of  the  deltoid  until  it  reaches  the  outer  edge  of  the  biceps  muscle  alongside  of  which 
it  passes  down  to  the  elbow.  This  vein  will  be  cut  as  the  inner  branch  of  the 
incision  is  made.  The  bicipital  groove,  when  the  palm  of  the  hand  faces  forward, 
lies  almost  directly  below  the  coraco-acromial  ligament.  While  the  incision  is  being 
made  the  arm  is  kept  rotated  slightly  outward. 

As  the  knife  descends  it  runs  along  the  inner  side  of  the  bicipital  groove  and 
divides  the  tendon  of  the  pectoralis  major  muscle.  As  soon  as  this  tendon  is  cut  the 
incision  is  inclined  laterally.  The  incision  having  been  carried  down  to  the  bone, 
except  on  the  inside  of  the  arm,  the  deltoid  flap  is  raised  upward  and  backward.  It 
carries  with  it  the  circumflex  nerve  and  posterior  circumflex  artery. 

The  disarticulation  of  the  bone  is  apt  to  be  bungled  unless  one  knows  the  con- 
struction of  the  parts.  It  is  to  be  borne  in  mind  that  the  capsular  ligament  is  to  be 
divided  together  with  the  tendons  of  the  muscles  inserted  into  the  tuberosities.  The 
capsule  does  not  pass  across  the  anatomical  neck  to  be  inserted  into  the  tuberosities 
beyond,  and  the  mistake  is  often  made  of  cutting  on  the  anatomical  neck  and  there- 
fore frequently  the  capsule  still  remains  attached  to  the  proximal  side.  The  cut 
may  be  commenced  posteriorly  and  should  be  made  o?l  the  head  of  the  bone  just 
above  the  anatomical  neck.  The  arm  is  to  be  adducted  and  rotated  inward  and  the 
muscles  inserting  into  the  greater  tuberosity  cut  in  their  order,  first  the  teres  minor, 
then  the  infraspinatus  and  supraspinatus  with  the  joint  capsule  beneath  them.  Then 
comes  the  long  head  of  the  biceps,  and  the  arm  now  being  rotated  outward,  the 
tendon  of  the  subscapularis  is  divided.  In  cutting  the  muscles  and  capsule  across 
the  top  of  the  joint,  the  arm  is  to  be  kept  close  to  the  side  of  the  body  so  as  to  tilt 
the  upper  portion  of  the  capsule  out  beyond  the  acromion  process. 

The  head  of  the  bone  can  now  be  drawn  out  sufficiently  to  allow  the  knife  to  be 
introduced  behind  it  to  divide  the  inferior  portion  of  the  capsule.  This  should  be 
detached  close  to  the  bone  so  as  to  avoid  wounding  the  axillary  artery  and  especially 
the  posterior  circumflex  artery  and  the  circumflex  nerve,  which  wind  around  the 
surgical  neck  immediately  below  and  are  to  be  pushed  out  of  the  way. 

The  division  is  completed  by  cutting  the  remaining  muscles  passing  from  the 
trunk  to  the  shaft  of  the  bone.  On  the  inner  side  may  be  an  uncut  portion  of  the 
pectoralis  major,  the  coracobrachialis,  and  short  head  of  the  biceps ;  below  is  the  long 
head  of  the  triceps  and  on  the  outer  side  are  the  teres  major  and  latissimus  dorsi. 

On  examining  the  face  of  the  stump,  posteriorly  is  seen  the  bulk  of  the  deltoid 
muscle  with  the  triceps  below,  and  then  the  latissimus  dorsi  and  teres  major  tendons 
lying  next  to  the  artery.  Anteriorly  is  the  cut  edge  of  the  deltoid  and  pectoralis 
major  with  the  coracobrachialis  and  short  head  of  the  biceps  lying  next  to  the  artery. 

To  the  outer  side  of  the  artery  lie  the  median  and  musculocutaneous  nerves. 
To  the  inner  side  are  the  ulnar  and  lesser  internal  cutaneous  nerves  {cutaneus  brachii 
medialis)  and  the  axillary  vein.  Posteriorly  are  the  musculospiral  and  axillary 
(circumflex)  nerves. 

Sometimes  the  median  nerve  lies  in  front  instead  of  to  the  outer  side.  The  axillary 
artery  is  divided  below  the  origin  of  the  anterior  and  posterior  circumflex  arteries. 
The  bleeding  in  the  first  cut  will  be  from  the  cephaHc  vein  (which  runs  between 
the  pectoralis  major  and  deltoid),  muscular  branches  of  the  posterior  and  anterior 


2  so 


APPLIED    ANATOMY, 


circumflex,  a  small  ascending  branch  of  the  anterior  circumflex  which  runs  in  the 
bicipital  groove,  and  the  humeral  branch  of  the  acromial  thoracic  which  accompanies 
the  cephalic  vein. 

A  glaring  and  common  mistake  in  the  performance  of  shoulder  amputations  is 
the  making-  of  the  flaps  entirely  too  short,  especially  when  a  Larrey  operation  is 
attempted. 

The  avoidance  of  serious  hemorrhage  is  usually  accomplished  by  clamping  the 
small  vessels  as  the  operation  proceeds,  and  before  the  final  division  of  the  axillary 
vessels  slipping  the  fingers  behind  the  bone  and  compressing  them. 

Esmarch's  tube  has  been  used  by  encircling  the  shoulder  as  close  to  the  trunk 
as  possible,  the  tube  being  kept  from  slipping  by  a  bandage  passed  beneath  it  and 
fastened  to  the  opposite  side.  Wyeth's  pins  have  been  used  for  the  same  purpose. 
One  is  inserted  through  the  lower  edge  of  the  anterior  axillary  fold  a  little  internal 
to  its  middle  and  brought  out  above  in  front  of  the  acromion  process,  the  other  is 
entered  at  a  corresponding  point  of  the  posterior  fold  and  brought  out  above  just 
behind  the  angle  of  the  spine  of  the  scapula  or  acromion  process. 

Interscapulothoracic  Amputation. — For  malignant  growths  of  the  axilla, 
shoulder,  or  scapula,  and,  rarely,  for  injury,   the  whole  upper  extremity  with  the 


Cords  of  brachial  pie 


Omohyoid  muscle ^ 

Scalenus  antenor 

muscle 

Transverse  cer\  ical 

arter\ 


Internal  ]ugul 
Phrenic  ner- 
Suprascapular  artery 
Thoracic  duct 
Innommatc 


Subclavian  artery 

Superficial  cervical  artery 
Trapezius 

Posterior  scapular  artery  coming 
from  the  subclavian 
Costocoracoid  ligament 
Deltoid 


Subclavian  vein 

Acromial  thoracic  artery 

Fig.  264. — Structures  exposed  by  excising  the  inner  portion  of  the  clavicle. 


scapula  and  part  or  whole  of  the  clavicle  have  been  removed.  Anteroposterior 
flaps  are  made. 

The  greatest  danger  is  death  from  shock  and  hemorrhage.  In  order  to  obtain 
some  idea  of  the  topography  and  vessels  involved,  see  Fig.  264. 

Excision  of  the  Clavicle. — Excision  of  the  clavicle  in  the  living  body,  like 
tracheotomy,  is  much  more  difficult  than  when  practiced  on  the  dead  body;  this 
is  due  to  the  condition  of  the  parts  for  which  operation  is  undertaken.  It  has  been 
often  excised  for  malignant  growths.  On  the  upper  anterior  surface  are  attached  the 
clavicular  origin  of  the  sternomastoid,  the  deep  cervical  fascia,  and  the  trapezius 
muscle.  Crossing  the  clavicle  near  its  middle  is  the  jugulocephalic  vein  which  some- 
times connects  the  cephalic  with  the  external  jugular.  It  is  likewise  crossed  by  the 
superficial  descending  branches  of  the  cervical  plexus.  The  external  jugular  vein, 
about  2.5  cm.  (i  in.  )  above  the  middle  of  the  clavicle,  pierces  the  deep  fascia  and 
turns  inward  to  empty  into  the  internal  jugular  just  behind  the  outer  edge  of  the 
sternomastoid  muscle;  just  below  it  empties  the  thoracic  duct  at  the  junction  of  the 
internal  jugular  and  subclavian  veins.  The  subclavian  vein  is  directly  behind  the 
clavicle  and  the  left  innominate  vein  crosses  behind  the  left  sternoclavicular  joint  and 
passes  across  the  posterior  surface  of  the  sternum  just  below  or  on  a  level  with  its 


THE   SHOULDER-GIRDLE.  251 

superior  border.      The  omohyoid  muscle,  if  the  shoulder  is  drawn  outward  and  the 
head  turned  to  the  opposite  side,  is  drawn  upward  above  the  clavicle. 

■  Behind  the  upper  portion  of  the  clavicle  is  the  suprascapular  artery  and  above 
it  runs  the  transverse  cervical  artery,  a  branch  of  the  thyroid  axis.  Both  these 
vessels  cross  over  the  scalenus  anterior  muscle  on  which,  toward  its  inner  edge,  is 
lying  the  phrenic  nerve.  In  front  of  the  scalenus  anterior  runs  the  subclavian  vein 
and  behind  it  is  the  subclavian  artery  with  the  cords  of  the  brachial  plexus  above 
and  to  its  outer  side.  Below  and  in  front  are  attached  the  pectoralis  major  and 
deltoid  muscles;  the  space  between  them  forms  the  subclavicular  triangle  and  occu- 
pies the  outer  half  of  the  middle  third  of  the  bone.  The  cephalic  vein  pierces  the 
costocoracoid  membrane  at  this  point  to  enter  the  subclavian  vein. 

On  the  under  surface  of  the  bone  is  the  subclavius  muscle,  covered  with  a 
strong  membrane.  To  the  inner  side  of  this  muscle  is  the  costoclavicular  ligament. 
Beneath  the  clavicle,  about  its  middle,  passes  the  subclavian  artery,  separated  from 
the  vein  in  front  by  the  scalenus  anterior  muscle.  Below  and  beneath  the  subclavian 
artery,  which  rests  directly  on  it,  is  the  pleura.  The  internal  mammary  artery  passes 
behind  the  inner  extremity  of  the  clavicle  opposite  the  cartilage  of  the   first  rib. 

The  clavicle  is  the  first  bone  in  the  body  to  ossify,  and  it  has  one  epiphysis  at 
its  sternal  end  which  appears  about  the  seventeenth  year  and  joins  the  shaft  from 
the  twentieth  to  the  twenty-fifth  year.  In  removing  the  bone  it  is  first  loosened  at 
its  outer  extremity  by  dividing  the  acromioclavicular  and  coracoclavicular  (conoid 
and  trapezoid)  ligaments. 

Excision  of  the  Scapula. — The  removal  of  the  scapula  necessitates  the 
division  of  a  large  number  of  muscles,  for  which  see  pages  226  and  227.  The  sub- 
scapular artery  at  the  anterior  border,  about  2.  5  cm.  ( i  in. )  below  the  head  or  glenoid 
process,  and  the  suprascapular  at  the  suprascapular  notch,  are  to  be  ligated  before 
removing  the  bone.  Skirting  the  posterior  edge  is  the  posterior  scapular,  the 
continuation  of  the  transverse  cervical  artery;  it  is  to  be  avoided  when  detaching 
the  muscles.  The  acromial  branches  of  the  acromial  thoracic  artery  ramify  over  the 
acromion  process;  they  are  not  so  large  as  those  already  mentioned. 

Mr.  Jacobson  suggests  that  if  safety  permits  one  should  allow  the  acromion 
process  to  remain,  as  it  preserves  the  point  of  the  shoulder  and  to  some  extent,  the 
functions  of  the  trapezius  muscle. 

Excision  of  the  Head  of  the  Humerus. — The  incision  for  the  removal 
of  the  head  of  the  humerus  should  be  commenced  just  outside  of  the  coracoid 
process  and  be  carried  10  cm.  (4  in.)  downward  in  a  direction  toward  the  middle 
of  the  humerus,  where  the  deltoid  inserts.  This  incision  may  be  made  while  the  arm 
is  somewhat  abducted  but  it  does  not  go  in  the  groove  between  the  deltoid  and 
pectoralis  major  muscles.  This  groove  contains  the  cephalic  vein  and  the  humeral 
branch  of  the  acromial  thoracic  artery,  and  hence  is  to  the  inner  side  of  the  coracoid 
process  and  as  the  incision  is  to  the  outer  side,  it  passes  through  the  deltoid  near 
its  anterior  edge  (Fig.  265). 

The  incision  goes  through  the  muscle  and  exposes  the  capsule  of  the  joint.  The 
sides  of  the  wound  are  to  be  retracted  and,  if  the  long  head  of  the  biceps  muscle  is 
not  recognized  by  sight,  the  finger  is  inserted  and  the  arm  rotated.  The  bicipital 
groove  can  be  felt  and  the  tendon  identified. 

The  capsule  is  to  be  incised  along  the  outer  edge  of  the  long  tendon  of  the 
biceps  and  as  the  arm  is  rotated  inward  the  supraspinatus,  infraspinatus,  and  teres 
minor  muscles  are  to  be  detached  from  the  greater  (posterior)  tuberosity.  The 
biceps  tendon  is  again  brought  into  view  by  rotating  the  arm  outward  and  its  sheath 
(transverse  ligament)  slit  up  and  the  tendon  luxated  inward. 

The  attachment  of  the  capsule  and  subscapularis  muscle  to  the  lesser  (anterior) 
tuberosity  is  then  divided  while  the  arm  is  rotated  outward.  The  biceps  tendon  lies 
in  the  bicipital  groove  between  the  two  tuberosities.  When  the  arm  is  lying  with  the 
palm  upward,  in  a  supine  position,  the  bicipital  groove  looks  directly  anteriorly  in  a 
longitudinal  line  passing  midway  between  the  two  condyles  of  the  lower  end.  The 
position  of  the  head  and  groove  can  be  told  by  observing  the  position  of  the  condyles. 
The  head  is  directly  above  the  internal  condyle  and  the  groove  is  on  the  anterior  sur- 
face above  a  point  midway  between  the  condyles.      After  the  capsule  has  been  opened 


2S'2 


APPLIED    ANATOMY. 


and  the  attachments  of  the  muscles  to  the  greater  and  lesser  tuberosities  divided  and 
the  tendon  of  the  biceps  luxated  inward,  the  head  is  thrust  directly  upward  and  out 
of  the  wound  and  sawed  off  as  low  as  desired. 

Immediately  below  the  lower  edge  of  the  tuberosities  is  the  surgical  neck.  On 
it  anteriorly  winds  the  anterior  circumflex  artery,  and  posteriorly  the  circumflex  (axil- 
lary) nerve  and  posterior  circumflex  artery.  These  should  not  be  disturbed,  for  the 
artery  will  bleed  and  injury  of  the  nerve  will  cause  paralysis  of  the  deltoid  muscle. 

Posterior  and  transverse  incisions  have  been  suggested  for  this  operation  but 
they  are  not  to  be  advised.  The  circumflex  nerve  and  posterior  circumflex  artery 
are  almost  certain  to  be  injured  and  the  functions  of  the  deltoid  are  liable  to  be 
seriously  impaired  or  altogether  lost. 

If  more  access  is  desired  than  can  be  obtained  by  a  straight  incision  as  directed, 
the  deltoid  can  be  detached  from  its  origin  along  the  outer  end  of  the  clavicle  and 

Coracoid  process 


Acromion  process 

Subscapularis  tendo 
Lesser  tuberosity 
toid  muscle 


Fig.  265. — Resection  of  the  shoulder- 
subscapularis  on  the  stretch.  The  long  t 
held  to  the  inner  side  by  a  hook. 


The  arm  has  been  rotated  outward  so  as  to  put  the  tendo: 
of  the  biceps  has  been  dislocated  from  the  bicipital  groov 


acromion  process  and  turned  down.  This  does  not  interfere  with  its  nerve  supply. 
The  circumflex  nerve  going  to  the  muscle  crosses  the  humerus  at  about  the  junction 
of  the  upper  and  middle  thirds  of  the  deltoid  or  a  finger's  breadth  above  its  middle. 
After  resection  of  the  bone  the  deltoid  can  again  be  brought  up  and  sewed  to  its  pre- 
vious attachment. 

The  character  of  the  operation  depends  on  the  nature  and  extent  of  the  disease. 
The  operator  should  be  familiar  with  the  epiphyseal  line,  which  runs  from  the  inside 
upward  and  outward  in  the  line  of  the  anatomical  neck  as  far  as  the  middle  of  the 
bone,  and  then  slopes  slightly  downward  and  outward  to  reach  the  surface  almost  on 
a  level  with  the  lower  finner)  edge  of  the  articular  surface.  As  this  is  the  site  of 
most  active  growth  of  the  humerus  in  young  subjects  this  epiphyseal  cartilage  should 
be  spared  as  much  as  possible. 

The  disability  arising  from  a  free  resection  is  so  great,  owing  to  the  loss  of 
movements  resulting  from  the  detachment  of  muscles  and  interference  with  the 
epiphyseal  cartilage,  that  formal  resections  are  rarely  performed,  but,  instead,  the 
diseased  parts  are  simply  gouged  away  and  as  much  allowed  to  remain  as  possible. 


THE   SHOULDER-GIRDLE. 


253 


It  is  to  be  remembered  that  rotation  inward  is  mostly  performed  by  the  sub- 
scapularis  and  outward  rotation  by  the  infraspinatus  and  teres  minor.  The  supra- 
spinatus  aids  abduction.  A  too  free  excision  is  Hable  to  be  followed  by  a  ffail-joint, 
in  which  case  the  limb  hangs  helplessly  by  the  side  with  the  dorsum  pointing  forward. 

The  axillary  fold  muscles  insert  on  the  anterior  surface  of  the  bone  and  hence 
turn  the  arm  inward  and  draw  it  in  toward  the  body,  they  do  not  compensate  for 
the  loss  of  the  muscles  attached  to  the  tuberosities. 

The  bleeding  in  the  operation  will  be  mainly  from  the  acromial  branches  of  the 
acromial  thoracic  artery  and  the  bicipital  branch  of  the  anterior  circumflex  artery, 
which  runs  in  the  bicipital  groove. 

DISEASES  OF  THE  JOINT  AND  BURStE. 

The  shoulder-joint,  like  other  joints,  is  subject  to  inflammatory  arid  other  diseases. 
These  may  be  (i)  traumatic  and  later  septic;  (2)  rheumatic  or  gouty;  (3)  tuberculous, 
with  suppuration. 

These  affections  result  in  an  effusion  within  the  joint-cavity  which  distends  the 
capsule  and  finally  tends   to   escape  at   the  weakest  points.      The   joint   is   not  a 

Supraspmatus  Acromion  process 

Subacromial  bursa  space 
Capsule  of  joint 
Long  hell  of  biceps 


Capsule  of  joint 
Glenoid  cavity 
Long  head  of  triceps 

Fk;.  266. — Transverse  section  of  shoulder-joint,  illustrating  the  laxity  of  the  capsule  of  the  joint. 

complicated  one,  like  the  knee,  and  its  synovial  membrane  is  neither  so  extensive 
nor  so  elaborate. 

Traumatism  may  give  rise  to  a  synovitis,  an  inflammation  of  the  synovial  mem- 
brane, or  an  arthritis  involving  the  entire  joint  structures.  Sprains  and  other  injuries 
are  not  uncommon.  A  sprain  will  be  caused  by  a  force  which  acts  to  a  greater 
extent  than  the  normal  movements  of  the  joint  will  allow. 

Movements  of  the  Joint. — In  abduction  the  capsule  becomes  tense  at  its  lower 
portion  when  the  arm  is  at  90  degrees  to  the  trunk,  greater  abduction  is  resisted  by  the 
greater  tuberosity  impinging  on  the  acromion  process  and  the  scapula  begins  to  revolve. 

Adduction  is  resisted  both  by  the  muscles  and  by  the  ligaments.  When  the 
ligaments  only  remain,  the  head  can  be  separated  for  2  cm.  or  more  from  the  glenoid 
cavity  (see  Fig.  266).  Marked  adduction  is  usually  limited  by  the  arm  coming  in 
contact  with  the  side  of  the  body. 

If  the  humerus  is  brought  diagonally  across  the  chest  the  scapula  begins  to 
move  and  its  posterior  edge  and  lower  angle  turn  forward.  As  the  humerus  is 
adducted  the  deltoid  and  supraspinatus  are  made  tense  and  the  head  is  drawn  up  in 
its  socket.  When  the  muscles  are  paralyzed  the  weight  of  the  upper  extremity 
allows  the  head  to  fall  and  a  distinct  depression  can  be  seen  beneath  the  acromion 
process.      In  paralysis  of  the  deltoid  this  is  particularly  noticeable. 


254 


APPLIED    ANATOMY. 


If  traction  is  made  on  the  arm,  the  muscles  are  the  resisting  agents.  If  the  arm 
is  in  a  position  of  adduction,  those  going  from  the  humerus  to  the  scapula,  as  the 
deltoid,  supraspinatus,  biceps,  and  triceps,  act.  If  in  abduction,  then  also  those 
from  the  humerus  to  the  trunk,  Hke  the  pectoralis  major  and  latissimus  dorsi,  are 
brought  into  play.  The  part  played  by  the  deltoid  and  trapezius  should  be  noted. 
If  the  arm  is  down  by  the  side  and  traction  is  made  on  it,  the  force  is  transmitted 
from  the  humerus  in  a  direct  line  through  the  deltoid  and  the  upper  fibres  of  the 
trapezius  to  their  attachment  to  the  spine  and  superior  curved  line  of  the  occiput. 
If,  on  the  contrary,  the  traction  is  made  while  the  arm  is  raised  above  the  level  of  the 


Superior  acromioclavicular  ligament 


Acromion  process 


Conoid  ligament 
Trapezoid  ligament 

Coraco-acromial  ligament 
Coracoid  process 

Coracohumeral  ligament 
Coracobrachialis  muscle 
Short  head  of  biceps 


Long  head  of  biceps 


—  Pectoralis  major  muscle 


Fig.  267. — Acromiocl; 


shoulder,  the  force  is  transmitted  through  the  axillary  fold  muscles  as  well  as  by  the 
deltoid  and  continued  through  the  lower  fibres  of  the  trapezius.  In  either  case  the 
muscles  are  the  resisting  agents  and  not  the  ligaments.  Abduction  to  more  than  a 
right  angle  is  resisted  by  the  contact  of  the  greater  tuberosity  with  the  under  surface 
of  the  acromion  process  and  coraco-acromial  ligament  and  the  under  side  of  the  cap- 
sular ligament  is  made  tense.  The  raising  of  the  arm  to  90  degrees  is  performed 
by  the  supraspinatus  and  deltoid  muscles  of  the  scapula  and  beyond  this  by  the 
serratus  anterior  and  other  muscles. 

Inward  rotation  is  limited  by  the  infraspinatus  and  teres  minor  muscles  and  by 
tension  of  the  upper  portion  of  the  capsule.  Outward  rotation  is  limited  by  the  sub- 
scapularis  and  upper  portion  of  the  capsule. 


THE   SHOULDER-GIRDLE. 


255 


Subacromial  Bursa. — Separating  the  greater  tuberosity  from  the  deltoid 
muscle,  the  acromion  process,  and  coraco-acromial  ligament,  is  the  large  subacromial 
bursa.  It  does  not  communicate  with  the  joint,  except  rarely  in  old  people.  Effu- 
sions into  it  cause  an  increased  prominence  of  the  deltoid  muscle,  and  pus  seeking 
an  outlet  is  likely  to  show  itself  at  the  anterior  edge  of  the  muscle  and  less  often  at 
its  posterior  edge.  These  effusions,  which  are  liable  to  be  present  from  contusions, 
sprains,  etc. ,  should  not  be  mistaken  for  intra-articular  accumulations. 

Biceps  Tendon. — The  long  tendon  of  the  biceps  muscle  enters  the  joint 
through  the  bicipital  groove  between  the  two  tuberosities.  With  the  arm  hanging 
by  the  side  it  points  directly  forward;  it  passes  over  the  head  of  the  humerus  and 
under  the  coraco-acromial  ligament  about  midway  between  the  coracoid  and  acro- 
mion processes  to  insert  into  the  upper  edge  of  the  glenoid  cavity.  It  is  covered 
by  a  synovial  sheath  which  passes  with  it  through  the  opening  in  the  capsule  and  a 
short  distance  along  the  bicipital  groove.  As  this  sheath  does  not  communicate  with 
the  joint  the  tendon  is  in  one  sense  extra-articular.      It  is  held  in  the  groove  by  a 


Injection  following  the 
long  tendon  of  the  biceps 


Fig.  268. — Shoulder-joint  distended  with  injection,  showing  the  position  assumed  by  the  h 


fibrous  expansion,  extending  from  the  pectoralis  major  tendon  below  to  the  capsule 
above,  called  the  transverse  /umieral  ligament.  This  ligament  is  so  strong  that  luxa- 
tion of  the  tendon  is  uncommon;  even  when  the  humerus  is  luxated  the  tendon  is 
rarely  displaced. 

Subscapular  Bursa. — Beneath  the  tendon  of  the  subscapularis  there  is  a  bursa 
which  frequently  communicates  with  the  joint.  This  opening  tends  to  weaken  the 
capsule  and  it  is  at  this  point  and  just  below  that  the  head  bursts  through  in  disloca- 
tions. 

Infraspinatus  Bursa. — The  capsule  of  the  joint  and  the  synovial  membrane 
may  be  prolonged  beyond  the  rim  of  the  glenoid  cavity  under  the  tendon  of  the 
infraspinatus,  or  a  bursa  at  this  point  may  communicate  with  the  joint. 

Other  bursae  may  be  present,  but  are  .unimportant.  One  is  between  the 
coracoid  process  and  the  capsule  and  another  under  the  combined  tendon  of  the 
coracobrachialis  muscle  and  the  short  head  of  the  biceps. 

Effusions  in  the  Shoulder-joint. — Liquid  accumulations  occur  both  from 
injury  and  disease.  The  liability  of  confounding  them  with  those  in  the  subacromial 
bursa  has  been  alluded  to  above.  As  a  result  of  disease,  most  often  osteo-arthritis  or 
tuberculosis,  considerable  liquid  may  accumulate  in  the  joint.  As  the  tension  in- 
creases the  arm  becomes  abducted  about  50  degrees  and  the  effusion  tends  to  escape 
through  the  openings  in  the  capsule  (Fig.  268). 


2s6  APPLIED    AXATOMY. 

A  distention  of  the  joint  will  cause  the  deltoid  to  be  more  prominent.  If  the 
affection  is  in  an  old  person,  as  is  liable  to  be  the  case  in  osteo-arthritis,  there 
is  apt  to  be  a  communication  with  the  subacromial  bursa  and  this  will  become  dis- 
tended. If  the  liquid  is  purulent  it  has  a  tendency  to  work  its  way  laterally  under 
the  deltoid  and  break  through  at  its  anterior  or  posterior  borders  and  show  itself  at 
the  folds  of  the  a.xilla. 

In  osteo-arthritis  {arthritis  deformans)  the  long  tendon  of  the  biceps  as  it  passes 
through  the  joint  may  be  dissolved  and  the  belly  of  the  muscle  then  contracts  and  forms 
a  lump  on  the  middle  of  the  arm  anteriorly. 

Pus  frequently  finds  an  exit  along  the  bicipital  groove  and  follows  it  downward 
and  shows  itself  just  at  the  edge  of  the  anterior  axillary  fold  near  the  middle  of  the  arm. 

If  the  pus  passes  out  by  way  of  the  subscapular  bursa  it  passes  below  the 
subscapular  tendon  and  into  the  axilla  anteriorly.  If  it  passes  backward  it  may 
emerge  through  the  bursa  beneath  the  infraspinatus  muscle,  and  then  either  work  its 
way  downward  into  the  posterior  portion  of  the  axilla,  or  if  it  works  upward  may 
travel  either  above  or  below  the  spine  of  the  scapula  and  show  itself  on  the  dorsum. 

THE  AXILLA. 

The  axilla  is  a  wedge-shaped  space  with  its  apex  upward,  formed  between  the 
arm  and  chest  at  their  junction.  It  serves  as  a  passage-way  for  the  arteries,  veins, 
ner\'es,  and  lymphatics  passing  between  the  trunk  and  the  upper  extremity.  It  is 
frequently  the  site  of  growths  and  abscesses,  requiring  operations  which  necessitate  a 
knowledge  especially  of  its  blood-vessels  and  lymphatics. 

Extent. — Its  ape.x  lies  between  the  clavicle  and  scapula  above  and  the  first  rib 
beneath.  Its  base  is  formed  by  the  skin  and  fascia  stretched  between  the  anterior  and 
posterior  axillary  folds.  It  is  spoken  of  as  ha\'ing  four  walls:  inner,  outer,  anterior, 
and  posterior. 

The  inner  wall  is  formed  by  the  first  four  ribs  and  interspaces  and  the  corres- 
ponding serrations  of  the  serratus  anterior  (magnus)  muscle. 

The  outer  wall  is  nothing  more  than  the  chink  formed  by  the  union  of  the  two 
a.xillary  folds.  Above  is  the  lesser  tuberosity  of  the  humerus  and  subscapularis  ten- 
don, lower  down  are  the  coracobrachial  and  biceps  muscles. 

The  anterior  icall  is  formed  by  the  pectoralis  major  and  minor  muscles  with  the 
fascia  en\'eloping  them. 

The  posterior  wall  is  formed  by  the  subscapularis  above  and  the  teres  major  and 
latissimus  dorsi  muscles  below. 

Axillary  Fascia. — The  name  axillary  fascia  is  given  to  the  fascia  which  closes 
the  axillary  space  and  forms  its  base.  It  is  stretched  across  from  the  lower  edge  of 
the  pectoralis  major  in  front  to  the  lower  edge  of  the  teres  major  and  latissimus  dorsi 
behind.  On  the  inner  wall  it  is  continuous  with  the  fascia  covering  the  serratus 
anterior  (magnus)  and  side  of  the  chest;  when  it  reaches  the  \'essels  at  the  ape.x  of 
the  axilla  it  is  reflected  around  them  to  form  the  sheath. 

On  the  outer  wall  it  passes  from  the  pectoralis  major  in  front,  over  the  coraco- 
brachialis  muscle  beneath,  blends  with  the  sheath  of  the  vessels,  and  then  passes  to 
the  posterior  wall,  covering  the  subscapularis  abo^'e  and  the  teres  major  and  latissi- 
mus dorsi  below.  At  the  lower  edge  of  this  latter  muscle,  which  is  a  little  lower  than 
the  pectoralis  major,  it  passes  across  the  axilla  (Fig.  269). 

Anteriorly  the  fascia  covers  the  pectoralis  major  muscle;  at  its  lower  edge  it 
splits  to  co\'er  the  pectoralis  minor  muscle  and  forms  a  sheath  for  it.  As  the  axillary 
fascia  approaches  the  apex  of  the  axilla  where  the  superficial  vessels  enter,  it  becomes 
cribriform  in  character,  the  fascia  itself  being  wide-meshed  and  containing  fat  in  the 
interstices.  If  the  handle  of  the  scalpel  is  inserted  in  the  apex  of  the  axilla  and 
worked  backward  and  forward  two  arches  of  fascia  are  readily  formed,  one  convex 
toward  the  chest,  and  called,  the  "  Achselbogen,"  and  the  other  convex  toward  the 
arm,  called  the  "Armbogen"  {Langer,  Oester.  med.   Wocli.,  1846,  Nos.  15  and  16). 

The  fascia  on  the  superficial  surface  of  the  pectoralis  minor  is  called  the  elavz- 
pectoral  fascia.      At  the  upper  or  inner  border  of  the  pectoralis  minor  it  is  continuous 


THE    AXILLA.  257 

with  the  costocoracoid  membrane  which  goes  up  to  the  clavicle,  where  it  splits  to 
enclose  the  subcla\-ius  muscle  and  to  be  attached  to  the  anterior  and  posterior  borders 
of  the  clavicle.  The  upper  portion  of  this  costocoracoid  membrane  is  thickened  and 
forms  a  firm  band  which  runs  from  the  coracoid  process  to  the  cartilage  of  the  first 
rib,  and  is  called  the  costocoracoid  ligamenL. 

Between  this  ligament  above  and  the  upper  edge  of  the  pectoralis  minor  below, 
and  piercing  the  costocoracoid  membrane,  are  the  acromiothoracic  artery  and  vein, 
the  cephalic  vein,  the  superior  thoracic  artery,  external  anterior  thoracic  nerve,  and  a 
few  lymphatics  derived  from  the  breast.  The  superior  thoracic  artery  is  often  a 
branch  of  the  acromiothoracic  and  passes  behind  the  vein  to  supply  the  serratus 
anterior  and  intercostal  muscles  and  side  of  the  chest. 

The  fascia  on  the  under  surface  of  the  pectoralis  minor  unites  with  the  layer  on 
its  upper  surface,  and  passes  upward  to  the  coracoid  process  and  is  reflected  onto  the 


Pectoralis  maior 


Teres  major  and  latissimus  dorsi 

Fig.  269. — Axillary  fascia.  At  the  apex  of  the  axilla  the  fascia  is  almost  lacking,  forming  a  curved  arch  on 
the  side  toward  the  chest,  called  the  axillary  arch  or  "  Achselbogen."  The  curved  edge  toward  the  arm,  less  dis- 
tinct than  that  toward  the  chest,  is  called  the  "  Armbogen," 

vessels  to  aid  in  forming  their  sheath.      It  is  continuous  with  the  fascia  on  the  under 
surface  of  the  subclavius  muscle  and  the  deep  fascia  of  the  neck. 

This  portion  of  the  fascia  is  not  sufficiently  strong  to  form  an  absolute  barrier 
between  the  neck  and  axilla,  consequently  abscesses  forming  in  the  neck  will  break 
through  it  and  passing  under  the  clavicle  appear  in  the  axilla,  and  abscesses  starting 
in  the  axilla  may  burrow  under  the  cla\'icle  and  up  beneath  the  deep  fascia  of  the  neck. 

THE  AXILLARY  VESSELS. 

The  axillary  artery  and  vein  are  both  important.  The  avoidance  of  hemorrhage 
in  operations  in  this  locality  requires  skill  and  knowledge,  and  venous  bleeding  is 
more  apt  to  be  troublesome  than  arterial.  Wounds  of  the  vessels,  whether  artery 
or  vein,  of  those  portions  of  the  body  like  the  axillje,  groins,  or  base  of  the  neck  are 
particularly  dangerous;  the  blood  current  is  both  large  and  rapid. 

The  axillary  vein  drains  the  whole  upper  extremity  and  part  of  the  chest,  while 
the  axillary  artery  carries  all  the  blood  going  to  those  parts.  The  veins  being  so 
much  weaker  and  thinner  walled  than  the  arteries  is  the  reason  of  their  being  more 
frequently  injured.  Ligation  of  the  artery,  or  vein,  or  both,  may  cause  gangrene  of 
the  extremity  and  require  amputation. 

The  Axillary  Artery. — The  axillary  artery  begins  at  the  lower  border  of  the 
first  rib  and  ends  opposite  the  lower  border  of  the  folds  of  the  axilla  fteres  major). 
If  the  arm  is  lying  by  the  side  of  the  body  the  artery  describes  a  curve  with  its 


258  APPLIED    ANATOMY. 

convexity  outward.  If  the  arm  is  placed  straight  out  away  from  the  body,  the  artery 
is  straight.  If  the  arm  is  abducted  abo\'e  the  level  of  the  shoulder,  the  artery  again 
becomes  cun'ed  but  with  its  convexity  downward. 

The  line  of  the  aiicry  is  straight  only  when  the  arm  is  out  from  the  body,  when 
its  course  is  represented  by  a  line  drawn  from  the  middle  of  the  clavicle  to  the 
anterior  surface  of  the  elbow,  miduay  between  the  two  condyles.  It  passes  down 
alono-  the  inner  side  of  the  coracoid  process  and  the  coracobrachialis  muscle  about  at 
the  junction  of  the  anterior  and  middle  thirds  of  the  axilla.  It  is  divided  into  three 
parts  by  the  pectoralis  minor  muscle  (Fig.  270). 

First  Portion. — The  first  portion  of  the  axillary  is  usually  stated  to  be  2.5  cm. 
(i  in.)  in  length,  and  for  surgical  purposes  we  may  accept  this  as  a  working  basis. 

A.  H.  Young  has  pointed  out  that,  with  the  arm  out  from  the  body,  the  upper 
border  of  the  pe'ctoralis  minor  is  nearly  or  quite  level  with  the  lower  border  of 
the  first  rib,  but  the  muscle  leaves  the  side  of  the  chest  to  go  to  the  coracoid 
process  and  that  makes  an  interspace,  more  than  2.5  cm.  long,  above  its  upper  edge 

Pectoralis  major 
Deltoid 


Coracobrachialis 
Groove  for  axillary  vessels  and  nerves 
Long  head  of  triceps  muscle 

Teres  major  and  latissimus  dorsi  muscles 


of  the  axillary  artery. 

and  between  it  and  the  lower  edge  of  the  subclavius  muscle,  in  which  the  artery  can 
be  ligated.  In  the  first  portion  the  axillary  artery  above  the  pectoralis  minor  lies  too 
deep  to  be  compressed,  being  on  a  lower  level  than  the  pectoralis  major,  therefore 
it  is  better  to  compress  the  subclavian  above  the  clavicle. 

Brayiches. — The  first  portion  of  the  axillary  gives  off  two  branches,  the  superior 
thoracic  and  the  acromiothoracic  (thoraco-acromialis)  (Fig.  271  ). 

The  superior  thoracic  comes  off  posteriorly  and  winds  around  behind  the  axillary 
vein  to  supply  the  under  surface  of  the  pectoralis  minor,  intercostal  muscles,  serratus 
anterior,  and  side  of  the  chest.      It  is  a  small  vessel. 

The  acromiothoracic  {thoraco-acromialis)  is  a  short  large  trunk  which  comes  off 
anteriorly,  winding  around  the  edge  of  the  pectoralis  minor  and  piercing  the  costo- 
coracoid  membrane  to  divide  into  four  branches:  an  acromial,  to  the  acromion 
process;  a  humeral,  which  follows  the  cephalic  vein  between  the  deltoid  and  pecto- 
ralis major;  a  pectoral,  which  supplies  the  under  surface  of  the  pectoralis  major  and 
gives  branches  to  the  mammary  gland;  and  a  clavicular,  to  supply  the  subclavius 
muscle. 

Relations. — Posteriorly,  the  artery  lies  on  the  first  intercostal  space  and 
muscle,  the  second  and  pan  of  the  third  serrations  of  the  serratus  anterior,  the  pos- 
terior thoracic  nerve  (or  external  respiratory  of  Bell),  and  the  internal  anterior 
thoracic  nerve  to  the  pectoralis  minor  and  major. 


THE    AXILLA. 


259 


Internally. — To  the  inner  side  of  the  artery  and  somewhat  anteriorly  is  the 
axillary  vein ;  between  the  two  runs  the  internal  anterior  tJioracic  nerve.  As  the 
artery  and  vein  ascend  they  become  separated,  the  artery  to  pass  behind  and  the 
vein  in  front  of  the  scalenus  a._terior  muscle. 

Externally.  —  To  the  outer  side  and  above  the  artery  lie  the  cords  of  the 
brachial  plexus. 

Afiteriorly.—Ln  front  of  the  artery  are  the  skin  and  superficial  fascia,  the  edge 
of  the  pectoralis  major  muscle  and  fascia  covering  it,  the  costocoracoid  membrane 
pierced  by  the  acromiothoracic  artery,  cephalic  vein,  and  external  anterior  thoracic 
nerve,  which  goes  to  supply  the  pectoralis  major  muscle. 

Ligation  of  the  First  Portion  of  the  Axillary  Artery. — The  artery  lies 
deep  in  the  infracla\icular  triangle,  between  the  pectoralis  major  and  deltoid  muscles. 
It  can  be  approached  by  either  a  transverse  or  a  longitudinal  incision.  If  the  former 
is  used  it  should  be  made  through  the  skin  only,  immediately  below  the  clavicle, 
reaching  from  just  outside  the  sternocla\-icular  joint  to  the  coracoid  process. 

The  pectoralis  major  is  detached  from  the  clavicle  and  pushed  downward,  it 
arises  from  its  inner  half.      This  exposes  the  costocoracoid  membrane.      At  the  outer 


Pectoralis  minor 


Pectoralis  major  muscle 
^  Superior  thoracic 


Acromiothoracic 


Long  thoracic 


Triceps 
: . — Diagrammatic 


"  of  axillary  artery  and  its  branches. 


angle  of  the  wound  the  cephalic  vein  and  acromiothoracic  artery  are  to  be  found. 

The  deltoid  muscle  is  to  be  detached  or  pushed  outward  to  e.xpose  the  coracoid 
process,  this  being  recognized,  the  costocoracoid  membrane  is  to  be  opened  to  its 
inner  side,  between  it  and  the  cephalic  vein.  The  acromiothoracic  artery  if  isolated 
will  lead  to  the  artery,  while  the  cephalic  vein  goes  direct  to  the  subclavian  vein. 
The  vein  and  costocoracoid  membrane  are  closely  united  and  great  care  is  necessary 
to  avoid  wounding  the  former  in  opening  the  latter.  The  cords  of  the  brachial 
plexus  are  to  the  outer  side  of  the  artery  and  care  is  to  be  exercised  not  to  mistake 
one  of  them  for  the  artery.  As  the  vein  is  the  most  dangerous  structure,  it  is  to  be 
displaced  inward  and  the  aneurism  needle  passed  between  it  and  the  artery  from 
within  outward. 

As  the  e.xternal  anterior  thoracic  nen'e  is  a  nerve  of  motion  supplying  the 
pectoralis  major  muscle,  if  it  is  seen  it  should  be  avoided  and  not  injured. 

If  it  is  desired  to  use  a  longitudinal  instead  of  transverse  incision,  it  should  com- 
mence just  outside  the  middle  of  the  clavicle  and  follow  the  groove  between  the  deltoid 
and  pectoralis  major  muscles  downward  for  lo  cm.  (6  in. ).  Great  care  is  then  neces- 
sary to  avoid  wounding  the  cephalic  vein  and  acromiothoracic  artery,  which  lie  in  this 
groove. 

If  sufficient  exposure  is  not  given  by  a  single  straight  incision  it  can  be  supple- 
mented by  one  detaching  the  pectoralis  major  from  the  clavicle. 


26o 


APPLIED    ANATOMY, 


Second  Portion. — The  second  portion  of  the  axillary  lies  beneath  the  pecto- 
ralis  minor  muscle.  It  is  3  cm.  ( 1 34;  in.  )  long  and  while  never  ligated  at  this  point  it  is 
nevertheless  frequently  exposed  while  clearing  out  the  axilla  for  malignant  growths  of 
the  breast.  Owing  to  its  being  covered  by  the  pectoralis  minor  and  major  muscles 
the  artery  cannot  be  compressed  at  this  point  in  its  course. 

Bra7iches. — Its  branches  are  the  alar  thoracic  and  long  thoracic.  The  a/ar  tho- 
racic are  small  branches  of  litde  importance  supplying  the  fat  and  glands  of  the 
axilla. 

The  long  thoracic  or  external  mammary  is  of  considerable  importance  on  account 
of  its  size  and  because  it  is  encountered  in  operations  on  the  breast  and  axilla.  It 
passes  down  along  the  lower  (outer)  border  of  the  pectoralis  minor,  giving  branches 
to  it  and  the  pectoralis  major;  some  branches  go  to  the  axilla  and  serratus  anterior, 
and  others,  which  may  be  of  considerable  size  in  the  female,  wind  around  the  lower 
portion  of  the  pectoralis  major  or  pierce  it  to  supply  the  mammary  gland.      Posterior 


Coracobrachialis  and  sho^, 
hear!  of  biceps 
Musculocutaneous 

Lonff  thoracic  arte-j 

Subscapular  .t 
Posterior  circumflex  arterj- 
Pectoralis  uiajor  muscle 
Median 
Internal  cutaneous 


Intertostohuuieral  i 


-Dissection  of  the  axilla 


to  it  is  the  long  or  posterior  thoracic  ner\e,  or  external  respiratory  nen-e  of  Bell, 
going  to  supply  the  serratus  anterior  muscle  (Fig.  272). 

Relations.  — Anteriorly  is  the  pectoralis  minor  muscle,  superficial  to  which  is  the 
pectoralis  major  and  skin.  Posteriorly  lie  the  posterior  cord  of  the  brachial  plexus, 
the  fat  of  the  axilla,  and  the  subscapularis  muscle;  i7iternally  is  the  axillary  vein,  with 
the  inner  cord  of  the  brachial  plexus  separating  the  two.  Externally  is  the  outer 
cord  of  the  plexus  and  farther  out  is  the  coracoid  process. 

Third  Portion. — This  is  about  7.5  cm.  (3  in.)  long  and  runs  from  the  lower 
border  of  the  pectoralis  minor  to  the  lower  border  of  the  teres  major.  Its  upper 
portion  is  under  the  pectoralis  major  but  its  lower  portion  is  subcutaneous  because 
the  teres  major,  forming  the  edge  of  the  posterior  fold  of  the  axilla,  extends  lower 
than  the  anterior  fold.  It  is  here  that  the  axillary  artery  is  most  easily  reached  and 
most  often  ligated. 

Branches. — It  gives  off  three  branches,  the  subscapular,  the  anterior  circumflex, 
and  the  posterior  circumflex. 

The  subscaptdar  artery  is  of  considerable  practical  importance;  it  is  the  largest 
branch  of  the  axillary  and  is  given  off  opposite  the  lower  border  of  the  subscapularis 
muscle.      It  follows  the  lower  edge  of  this  muscle  down  the  axillary  or  outer  border 


THE  AXILLA.  261 

of  the  scapula  to  its  angle,  where  it  anastomoses  with  the  posterior  scapular,  one  of 
the  terminal  branches  of  the  transverse  cervical  from  the  thjToid  axis. 

Four  centimetres  (ij^  in.)  from  its  origin  the  subscapular  gives  ofi  the  dorsalis 
scapulce,  which  is  as  large  or  larger  than  the  continuation  of  the  artery'  dowm^ard. 
The  position  of  this  artery-  should  be  borne  in  mind  in  operating.  It  winds  around 
the  outer  edge  of  the  scapula  between  it  and  the  teres  minor  muscle  to  supply  the 
muscles  posteriorly.  The  subscapular  artery  is  accompanied  by  the  long  subscapular 
nerve  to  its  inner  side.  (The  first  or  short  subscapular  nerve  supplies  the  subscapu- 
laris  muscle,  the  second  supplies  the  teres  major  and  the  third  or  long  subscapular 
supplies  the  latissimus  dorsi  muscle. ) 

The  posterior  axillan.^  chain  of  lymph-nodes  accompanies  the  subscapular  artery, 
hence  it  is  involved  in  operations  for  their  removal.  The  point  at  which  the  dorsalis 
scapuke  winds  around  the  axillary  border  of  the  bone  is  at  or  just  above  the  level  of  the 
middle  of  the  deltoid  muscle  and  below  the  le\el  of  the  posterior  circumflex  arter}-. 

The  anterior  circumflex  artery  is  comparatively  insignificant.  It  winds  ante- 
riorly around  the  surgical  neck  of  the  humerus  beneath  the  coracobrachialis  muscle 
and  both  heads  of  the  biceps  and  gives  off  an  ascending  bicipital  branch  which  ascends 
in  the  bicipital  groo\'e  and  a  small  descending  branch  to  the  tendon  of  the  pectoralis 


Coracobrachialis  muscle 


Internal  cutaneous  i 
Fig.  273. — Ligation  of  the  third  portion  of  the  a.xillary  artery. 

major.  As  pointed  out  by  Walsham,  the  anterior  circumfle.x  artery  on  account  of 
the  closeness  %vith  which  it  hugs  the  bone  may  be  difficult  to  secure  if  wounded  in  the 
operation  of  resection  of  the  humertis. 

The  posterior  circumflex  arter}-  is  much  larger  than  the  anterior.  It  runs  around 
the  surgical  neck  posteriorly,  below  the  teres  minor,  above  the  teres  major,  and 
between  the  long  head  of  the  triceps  and  the  humerus.  It  is  accompanied  by  the 
circumfle.x  'axillary)  nerve  and  they  run  transversely  around  beneath  the  deltoid 
muscle  on  a  le\-el  with  the  junction  of  its  upper  and  middle  thirds.  It  is  to  avoid 
wounding  these  t\vo  important  structures  that  the  operation  of  resection  is  done 
anteriorly  instead  of  posteriorly.  Being  co\'ered  only  by  the  skin  of  the  axilla  and  the 
superficial  and  deep  fascias,  it  can  readily  be  compressed  bv  pressure  directed  out- 
wardly against  the  humerus  along  the  irmer  edge  of  the  coracobrachialis  muscle. 

Relations. — Posteriorly  the  third  portion  of  the  axillary-  arter}"  lies  on  the  sub- 
scapularis,  the  latissimus  dorsi,  and  teres  major  muscles,  with  the  musculospiral  and 
circumflex  (axillar}-)  ner\'es  between  the  muscles  and  the  arten,-. 

Anteriorly  it  is  covered  by  the  skin  and  fascia,  the  pectoralis  major  abo\-e,  and 
deep  fascia  of  the  arm  below.  The  inner  root  of  the  median  ner\-e  crosses  it  and 
sometimes  the  outer  vena  comes. 


262 


APPLIED    ANATOMY. 


Acromiothoracic 

Posterior  circumflex 
Anterior  circumflex 
Subscapular 
Alar  thoracic 


Externally  is  the  coracobrachial  muscle  (which  partly  o\-erlaps  it  and  forms  its 

guide) ,  the  main  trunk  and  outer  head  of  the  median,  and  the  musculocutaneous  ner\'es. 

Interyially  is  the  axillary  vein  with  the  ulnar  nen-e  between  it  and  the  artery. 

The  internal  and  lesser  internal  cutaneous  nerves  also  lie  to  its  inner  side  with  the 

former  the  more  anterior. 

Ligation  of  the  Third  Portion  of  the  Axillary  Artery. — The  arm  being 
placed  out  from  the  body,  palm  upward,  the  incision  for  ligating  the  axillary  artery  in 
the  third  portion  of  its  course  is  laid  along  the  inner  border  of  the  coracobrachial 
muscle,  at  about  the  junction  of  the  anterior  and  middle  thirds  of  the  axilla  and  on  a 
line  joining  the  middle  of  the  clavicle  and  a  point  at  the  bend  of  the  elbow  midway 
between  the  two  condyles  of  the  humerus. 

The  middle  of  the  incision  should  be  just  above  the  lower  edge  of  the  folds  of 
the  axilla.      The  deep  fascia  having  been  opened,  the  coracobrachial  muscle  with  the 

musculocutaneous  nerve  piercing  it  is 
pulled  outward.  Lying  on  the  artery 
to  its  outer  side  is  the  median  nen-e; 
it  is  to  be  drawn  outward.  To  the 
inner  side  lies  the  axillary  vein  with 
the  ulnar  ner\e  beneath  it  and  the 
internal  cutaneous  nerve  (cutaneus 
antebrachii  medialis)  in  front  of  it 
close  to  the  artery. 

The  needle  is  passed  from  within 
outward.  The  artery  at  this  point  may 
be  crossed  by  some  muscular  fibres 
coming  from  the  latissimus  dorsi  and 
crossing  the  axilla.  The  axillary  vein 
is  the  continuation  of  the  basilic  from 
the  lower  border  of  the  teres  major 
upward. 

Of  the  two  A'enae  comites  of  the 
brachial  artery  the  inner  one  blends 
with  the  basilic  at  the  lower  border 
of  the  teres  major;  the  outer  one 
crosses  the  artery  to  empty  into  the 
axillary  vein  on  the  opposite  side. 

The  axillary  \€\n  receives  the 
subscapular,  circumflex,  long  thoracic, 
acromiothoracic,  alar,  and  cephalic, 
and  contains  a  pair  of  -valves  opposite  the  lower  border  of  the  subscapularis  muscle. 
Collateral  Circulation  after  Ligature  of  the  Axillary  Artery. — If  the 
first  portion  of  the  axillary  is  tied,  the  acromiothoracic  artery  comes  off  so  low  down 
(under  the  edge  of  the  pectoralis  minor  muscle  almost)  that  the  ligature  is  placed 
above  it,  in  which  case  the  collateral  circulation  is  similar  to  that  of  the  subcla\ian 
(see  page  149).  The  second  portion  of  the  axillary,  lying  beneath  the  pectoralis 
minor,  is  not  subject  to  ligation.  In  the  third  portion  the  subscapular  and  anterior 
and  posterior  circumflex  arteries  come  of!  so  close  together  that  the  ligature  will  be 
placed  either  just  below  or  just  above  them  (Fig.  274). 

If  below,  then  the  collateral  circulation  «'ill  be  between  them  above  and  the 
superior  profunda  below.  If  above  the  subscapular,  then  the  anastomosis  would  be 
as  follows: 

Proximal  Vessels.  Distal  Vessels. 

Acromiothoracic,  acromial  branch with  anterior  and  posterior  circumflex 

Acromiothoracic,  humeral  branch with  anterior  and  posterior  circumfle.x 

Acromiothoracic,  pectoral  branch with  subscapular 

Long  thoracic  branch with  subscapular 

Alar  thoracic  branch with  subscapular 

Posterior  scapular  (branch  of  trans,  cervical)  with  subscapular  and  dorsalis  scapulae 

Suprascapular      with  dorsalis  scapulae  and  posterior 

circumflex 


-Collateral  circulation  after  ligation  of  the  third 
portion  of  the  axillary  artery. 


THE  AXILLA. 


263 


Lymphatics  of  the  Axilla. — There  are  two  sets  of  lymphatic  nodes  in  the 
axillary  region,  the  axillary  rtodes  proper  and  the  subclavian  nodes. 

The  number  of  the  nodes  varies  from  about  ten  or  twelve  to  twenty  or  more. 
When  enlarged  they  are  readily  seen,  but  after  the  surgeon  has  carefully  dissected 
away  all  the  nodes  he  can  possibly  find  disease  may  subsequently  reveal  the  exist- 
ence of  others.  Hence  it  is  impossible  ever  to  be  absolutely  sure  that  all  nodes  have 
been  removed. 

The  subclavian  nodes,  about  two  or  three  in  number,  lie  in  the  infraclavicular 
triangle  between  the  pectoralis  major  and  deltoid  muscles  and  on  the  front  of  the 
subclavian  vein  above  the  pectoralis  minor  muscle.  They  receive  radicles  from  the 
mammary  gland  as  well  as  from  the  axillary  groups. 

The  axilla}'}'  nodes  proper  are  composed  of  three  sets,  humeral  or  external, 
thoracic  or  anterior,  and  scapular  or  posterior,  accompanying  the  three  vessels, 
axillary,  long  thoracic,  and  subscapular. 

The  humeral  set,  perhaps  eight  or  nine,  accompany  the  axillary  artery  and 
vein  and  lie  along  them  and  in  the  axillary  fat.      They  receive  mainly  the  lymphatics 


Deltopectoral 


Subscapular  node 


Anterior  pectoral 


Inferior  pectoral 


Intermediate  node 


Subareolar  plexus 
over  mammary 
gland 


Fig.  275. — Lymphatics  of  mammary  gland. 


dllary  nodes.     (Poirier  and  Cuneo.) 


from  the  arm.  They  can  often  be  pared  of?  the  vessels  with  ease,  but  sometimes 
are  so  firmly  attached  that  the  vessels  are  injured  in  their  removal. 

The  anterior  or  thoracic  set  accompany  the  long  thoracic  artery  along  the  lower 
border  of  the  pectoral  muscles.  They  are  not  so  numerous  as  the  humeral  set, 
perhaps  four  or  five  in  number,  and  drain  the  anterior  upper  half  of  the  chest  above 
the  umbilicus,  including  the  mammary  gland  (Fig.  275). 

The  posterior  or  scapular  set  accompany  the  subscapular  artery  along  the  pos- 
terior portion  of  the  a.xilla.  They  are  about  as  numerous  as  the  anterior  set  and 
drain  the  upper  posterior  portion  of  the  chest,  the  scapula  and  lower  portion  of  the  neck. 

The  lymphatics  of  the  middle  and  lower  portion  of  the  back  as  low  down  as  the 
umbilicus  (3  to  4  cm.  above  the  iliac  crest)  also  drain  into  the  a.xilla. 

These  lymphatic  nodes  communicate  with  one  another,  so  that  it  does  not  of 
necessity  follow  that  if  the  part  ordinarily  drained  by  a  certain  set  is  affected  the 
nearest  nodes  will  be  involved.  It  usually  is  so,  but  not  always.  The  infection  may 
pass  by  or  through  one  set  of  nodes  and  involve  a  neighboring  communicating  set. 
It  happens  in  carcinoma  of  the  breast  that  sometimes  the  posterior  or  scapular  set  are 


264 


APPLIED    ANATOMY. 


involved  and  the  anterior  or  thoracic  set  escape.  This  has  ah"eady  been  alluded  to 
in  the  section  on  the  mammary  gland  (see  page  184).  These  three  sets  drain  into 
the  subclavian  nodes  and  then  empty  into  the  subclavian  vein  near  its  junction  with 
the  jugular. 

Abscess  of  the  Axilla. — Pus  forms  in  the  axillary  region  from  ordinary'  pyo- 
genic organisms  which  may  or  may  not  be  associated  with  specific  organisms  like 
the  tubercle  bacillus.      Abscesses  may  be  either  superficial  or  deep. 

The  skin  of  the  axilla  is  thin,  loose,  and  abundantly  supplied  with  sebaceous 
glands  connected  with  the  hair-follicles  and  sweat-glands.  These  glands  are  in  the 
deeper  layer  of  the  skin  and  are  superficial  to  the  axillary  fascia,  hence  abscesses 
originating  from  them  tend  to  break  externallv;  usually  they  do  not  become  large 
nor  extend  deep  into  the  axilla. 

Absce.sses  originating  from  the  lymphatics,  on  the  contrary,  may  be  either  deep  in 
the  axilla  along  the  a.xillary,  pectoral,  or  subscapular  vessels,  or  they  may  be  in  the 
axillary  fat  and  tend  to  point  toward  the  skin.  If  the  lymphatics  along  the  axillary 
vessels  are  the  point  of  origin,  the  abscess  may  follow  them  down  under  the  deep 
fascia  to  the  elbow.  If  the  nodes  high  up  are  invoh'ed,  the  abscess  may  work  up 
under  the  clavicle  into  the  neck.      If,  however,  the  nodes  near  the  apex  of  the  axilla 


Fig.  2  70. — Subpectoral  abscess. 

form  the  starting-point  then  the  abscess  bulges  through  the  cribriform  portion  of  the 
axillary  fascia  (between  the  "  Armbogen  "  and  "  Achselbogen  " )  into  the  a.xilla 
and  tends  to  discharge  through  the  skin.  Abscesses  originating  in  the  pectoral 
group  of  lymphatics  point  at  the  lower  margin  of  the  anterior  axillary  fold.  The 
attachment  of  the  serratus  anterior  to  the  side  of  the  chest  prevents  them  from  work- 
ing towards  the  back. 

Abscesses  involving  the  subclavian  nodes  may  cause  a  siibpedoi'al  abscess  (Fig. 
276).  The  pus  collects  superficial  to  the  costocoracoid  membrane  and  clavipectoral 
fascia  and  pushes  the  pectoralis  major  muscle  outward,  forming  a  large  rounded 
prominence  below  the  inner  half  of  the  clavicle.  The  pus  cannot  extend  upward  or 
toward  the  median  line  on  account  of  the  attachment  of  the  pectoralis  major  muscle. 
It  can  burrow  through  the  intercostal  spaces  and  invoh'e  the  pleural  cavity,  or  break 
through  the  fibres  of  the  pectoralis  major  anteriorly  or  between  the  pectoralis  major 
and  deltoid,  or,  as  is  most  commonly  the  case,  work  its  way  under  the  pectoralis 
major  muscle,  over  the  pectoralis  minor,  until  it  reaches  the  border  of  the  pectoralis 
major  at  the  anterior  fold  of  the  axilla. 

In  emptying  these  abscesses  an  incision  is  to  be  made  along  the  anterior  axillary 
fold  and  a  tube  introduced  beneath  the  pectoralis  major. 

Incision  for  Axillary  Abscess. — In  opening  an  axillary  abscess  one  should  bear  in 
mind  that  the  important  veins  and  nerves  accompany  the  arteries  and  that  the  arteries 
lie  in  three  places,  viz. ,  externally  along  the  humerus,  anteriorly  along  the  edge  of  the 
pectoral  muscles,  and  posteriorly  along  the  edge  of  the  scapula ;  therefore  these  three 
localities  are  to  be  avoided  and  an  incision  made  in  the  middle  of  the  axilla  and  short 
enough  not  to  endanger  the  brachial  vessels  on  the  outside  or  the  long  thoracic  or 
subscapular  on  the  inside  near  the  chest-wall. 

The  incision  may  divide  the  skin  and  if  desired  the  deeper  structures  can  be 
parted  by  introducing  a  closed  hsemostatic  forceps  and  separating  its  jaws. 


THE    AXILLA.  265 

Axillary  abscesses,  if  of  slow  formation  and  unopened,  tend  to  burrow  and  follow 
the  vessels  upward  beneath  the  clavicle  and  appear  in  the  supraclavicular  space  beneath 
the  deep  cervical  fascia,  and  they  may  even  enter  the  superior  mediastinum.  They 
may  also  descend  the  arm  under  the  fascia  covering  the  coracobrachialis  muscle. 

Axillary  Tumors. — Tumors  of  the  axilla  are  almost  always  due  to  involvement 
of  the  lymph-nodes.  They  may  be  either  benign  and  inflammatory  in  character,  form- 
ing the  ordinary  axillary  adenitis,  or  tuberculou.s,  or  they  may  be  malignant.  As 
they  are  due  to  disease  of  the  lymph-nodes,  the  parts  which  the  glands  drain  should 
be  searched  for  the  starting-point  of  the  affection.  Aneurism  or  abscess  may  be 
mistaken  for  a  new  growth  and  an  inflamed  aneurism  may  readily  be  thought  to  be 
an  abscess. 

The  excision  of  axillary  tumors  is  difficult;  If  the  tumor  is  of  an  inflammatory 
origin  it  may  be  closely  adherent  to  the  veins  or  arteries  or  ner\'es,  and  the  same  con- 
dition may  exist  in  malignant  cases. 

The  blood  supply  of  the  axilla  is  so  free  that  nothing  is  to  be  gained  by  saving 
small  vessels,  therefore  in  paring  a  tumor  off  the  axillary  vessels  the  various  small 
branches  are  ligated  and  divided  and  the  main  vessels  left  bare.  This  applies  to  the 
veins  as  well  as  the  arteries. 

The  subscapular  artery  is  so  large  that  it  is  often  aUowed  to  remain.  When 
working  in  the  posterior  portion  of  the  axilla  it  is  to  be  remembered  that  the  pos- 
terior circumflex  artery  is  opposite  the  surgical  neck  of  the  humerus,  above  the 
tendon  of  the  latissimus  dorsi  muscle,  and  that  the  subscapular  artery  is  on  the 
opposite  side  of  the  axillary  artery  a  little  higher  up.  The  large  subscapular  vein 
will  bleed  profusely  if  wounded  and  it  should  be  looked  for  at  the  axillary  border  of 
the  scapula  below  the  subscapularis  muscle. 

Wounds  of  the  axillary  vein  are  particularly  dangerous  on  account  of  the  admis- 
sion of  air.  The  attachment  of  the  vein  to  the  under  side  of  the  pectoralis  minor  and 
costocoracoid  membrane  keeps  it  from  collapsing;  hence  the  danger. 

Nerves  of  the  Axilla. — The  brachial  plexus  is  above  the  first  portion  of  the 
axillary  artery.  In  the  second  portion  one  cord  is  to  the  inner  side,  one  to  the 
outer,  and  one  behind.  In  the  third  portion  the  median  nerve  is  anterior  and  a  little 
to  the  outer  side  of  the  artery,  being  formed  by  two  roots,  one  from  the  inner  and 
the  other  from  the  outer  cord  of  the  brachial  plexus. 

The  musculocutaneous  nerve  is  to  the  outer  side  of  the  artery,  leaving  the  outer 
cord  to  enter  the  coracobrachialis  muscle.  The  ulnar,  internal  cutaneous  (cidaneus 
antebrachii  medians'),  and  lesser  internal  cutaneous  {cutaneus  brachii  medians')  come 
from  the  inner  cord  and  lie  to  the  inner  side  of  the  artery.  From  the  posterior  cord 
come  the  axillary  (circumflex)  and  radial  (jnusculospiral)  nerves.  On  the  inner  wall 
of  the  axilla  behind  the  long  thoracic  artery  is  the  N.  tlioracalis  longus  (long  thoracic, 
or  external  respiratory  nerve  of  Bell);  it  is  a  motor  nerve  and  supplies  the  serratus 
anterior  (niagnus)  muscle,  hence  it  is  not  to  be  injured  in  clearing  out  the  axilla. 

Still  farther  posteriorly,  accompanying  the  subscapular  artery,  is  the  thoraco- 
dorsalis  or  long  subscapular  nerve.  It  also  is  a  motor  nerve  supplying  the  latissimus 
dorsi  muscle;  therefore  it  is  to  be  spared. 

Crossing  the  axilla  from  the  second  intercostal  space  to  anastomose  with  the 
cutaneus  brachii  medialis  nerve  is  the  intercostobrachial  (^humeral)  nerve.  It  is  a 
nerve  of  sensation  and  need  not  be  spared.  Sometimes  another  branch  from  the 
third  intercostal  nerve  also  crosses  the  axilla;  it  is  also  sensor}^  and  can  be  cut  away. 

As  the  axillary  (circumflex)  nerve  normally  winds  around  the  surgical  neck 
of  the  humerus,  when  luxation  occurs  it  is  stretched  over  the  head  and  paralysis  of 
the  deltoid  may  ensue. 

The  various  nerves  of  the  brachial  plexus  are  often  injured  by  pressure  resulting 
from  the  use  of  crutches  ("crutch  palsy").  It  is  liable  to  affect  any  or  several  of 
the  nerves,  the  radial  (musculospiral)  probably  the  most  frequently.  Neuritis  is 
common  and,  as  in  injuries,  the  nerves  affected  are  recognized  by  the  motor  or 
sensory  symptoms  produced. 


266 


APPLIED    ANATOMY. 


THE    ARM. 

The  arm — or  upper  arm — is  formed  by  a  single  bone  surrounded  by  muscles, 
which,  with  the  exception  of  the  biceps,  are  attached  to  it.  The  main  vessels  and 
most  of  the  important  nerves  run  down  its  inner  side.  It  receives  from  the  trunk  the 
insertions  of  the  muscles  which  move  it,  and  gives  origin  to  the  muscles  which  move 


Anatomical  necl 


Greater  tuberosity. 
Lesser  tuberosity- 
Bicipital  groove- 
Surgical  neck 


Pectoralis  majo: 


Brachioradialis 


Extensor  carpi, 
radialis  longior 


Radial  fossa 


the  forearm.  It  is  more  subject  to  injury  than  to  disease;  infection,  caries,  and 
rickets  may  attack  the  bone  and  rarely  new  growths  may  occur,  but  its  common 
affections  are  wounds  involving  the  muscles,  blood-vessels,  or  nerves,  and  fractures 
of  the  bone.      Severe  injuries  occasionally  necessitate  amputation. 


THE   ARM. 


267 


THE    HUMERUS. 

The  humerus  is  a  long  bone  with  a  large  medullary  cavity.  Its  shaft  is  com- 
posed of  compact  tissue  and  its  ends  of  cancellous  tissue.  _  In  shape  it  is  like  the 
letter  /,  that  is,  convex  anteriorly  above  and  concave  anteriorly  below.  At  the  mid- 
dle of  the  bone  on  its  external  surface  is  the  rough  deltoid  eminence  for  the  insertion 
of  the  deltoid  muscle. 

Anterior  Surface. — Separating  the  tuberosities  above  and  running  down  the 
anterior  surface  is  the  bicipital  groove.  Its  external  lip  receives  the  insertion  of  the 
pectoralis  major  muscle,  its  inner  lip  and  floor  those  of  the  latissimus  dorsi  above  and 
the  teres  major  below.  On  its  inner  side  at  and  a  litde  below  its  middle,  is  the 
insertion  of  the  coracobrachialis  muscle.      On  the  anterior  surface  from  the  deltoid 


Pectoralis  major 


Pectoral 
Long  head  of  biceps. 
Short  head  of  biceps- 

Coracobrachialis.^^    /^ 


Inner  head  of  triceps 


Fig.  279. — Muscles  of  the  anterior  and  internal  aspects  of  the  region  of  the  shoulder. 

eminence  to  the  elbow-joint  is  the  origin  of  the  brachialis  anticus;  it  has  two  heads, 
which  embrace  the  insertion  of  the  deltoid,  one  being  in  front  and  the  other  behind 

it  (Fig.  277).  

Posterior  Surface. — On  the  posterior  surface,  runnmg  obliquely  across  the 
bone  downward  and  outward,  below  the  insertion  of  the  deltoid,  is  a  shallow  groove, 
called  the  musculospiral  groove  {sulcus  radians').  It  holds  the  musctilospiral 
(radial)  nerve  and  the  superior  profunda  artery.  Above  the  groove  and  to  its 
outer  side  is  the  origin  of  the  outer  head  of  the  triceps  extensor  muscle  and  the 
insertion  of  the  deltoid.  To  its  inner  side,  below,  is  the  origin  of  the  inner  head 
of  the  triceps.  Therefore  the  groove  separates  the  inner  head  of  the  triceps  muscle 
from  the  outer  (Fig.  278). 

MUSCLES  OF  THE  ARM. 
In  order  to  operate  intelligently  it  is  necessary  to  know  the  muscles  and  inter- 
spaces, for  the  latter  carry  important  structures.  The  arm  possesses  four  sets  of 
muscles.  One,  an  external  set,  abducts  it,  the  deltoid ;  another,  or  internal  set,  ad- 
ducts  it  (and  rotates  it  inward),  the  pectoralis  major,  teres  major,  latissimus  dorsi, 
and  coracobrachialis ;  another,  anterior  set,  flexes  the  forearm,  the  biceps,  and  the 
brachialis  anticus;  and  the  last,  or  posterior  set,  extends  the  forearm,  the  triceps,  with, 
sometimes,  the  subanconcus  beneath  it. 


268 


APPLIED    ANATOMY 


The  External,  or  Abductor  Set. 

This  comprisL'S  only  one  muscle,  the  deltoid;  the  supraspinatiis  belongs  to  the 
shoulder  region. 

The  deltoid  forms  the  large  rounded  prominence  of  the  shoulder.  At  its 
insertion  the  bone  is  nearest  the  surface  and  can  be  most  readily  felt.  The  posterior 
edge  can  be  plainly  seen  when  contracted  running  upward  and  inward  and  crossing 


Acromion  process  — 

Coracoid  process 
Deltoid 
Long  head  of  biceps  — 

Short  head  of  biceps  — 
Pectoralis  major 

Biceps  (cut  edge) 


Brachialis  ant 


Coronoid  process  of  ulna 


Fig.  280. — Anterior  view  of  muscles  of  the  arm. 

the  posterior  fold  of  the  a.xilla  at  right  angles.      Its  anterior  edge  blends  more  or 
less  completely  with  the  pectoralis  major  TFig.  279). 

The  Internal  Set. 
The  internal  set  includes  the  coracobrachialis,  with  the  short  head  of  the  biceps, 
and  the  pectoralis  major,  teres  major,  and  latissimus  dorsi. 


THE   ARM.  269 

The  coracobrachialis  arises  from  the  coracoid  process  and  tendon  of  the  short 
head  of  the  biceps  and  inserts  on  the  inner  surface  of  the  humerus  for  a  distance  5  to 
7.5  cm.  (2  to  3  in.)  opposite  the  insertion  of  the  deltoid,  but  extending  a  Httle  lower. 
In  its  course  from  the  coracoid  process,  in  its  lower  part,  it  is  subcutaneous  and  pro- 
duces a  distinct  muscular  prominence  along  the  anterior  border  of  the  axilla.  It 
occupies  about  one-third  of  the  width  of  the  axilla  and  is  a  guide  to  the  brachial 
artery.  Below  the  edge  of  the  anterior  axillary  fold  it  dips  down  to  insert  into  the 
bone  and  is  covered  bv  the  biceps  muscle.  The  inner  edge  of  the  coracobrachialis 
is  continuous  with  the  inner  edge  of  the  biceps.  When  it  contracts  it  adducts  the 
humerus  and  brings  it  forward. 

The  pectoralis  major,  forming  the  anterior  axillary  fold,  inserts  into  the 
external  lip  of  the  bicipital  groove  from  the  greater  tuberosity  above  to  the  insertion 
of  the  deltoid  below.  The  tendon  is  twisted  on  itself  so  that  the  lowest  fibres  at  its 
origin  are  inserted  the  highest,  and  the  highest  in  origin  are  the  lowest  at  their 
insertion. 

The  latissimus  dorsi  and  teres  major  form  the  posterior  axillary  fold  and 
their  manner  of  insertion  reseml;les  that  of  the  pectoralis  major.      The  tendon  of  the 


latissimus  dorsi  inserts  into  the  bottom  of  the  bicipital  groo\e  higher  up  than  the 
teres  major.  Hence  near  the  humerus  the  lower  edge  of  the  posterior  a.xillary  fold 
is  formed  by  the  teres  major  and  its  lower  border  marks  the  lower  limit  of  the  axillajy 
and  the  beginning  of  the  bi'achial  artery. 

As  the  pectoralis  major,  latissimus  dorsi,  and  teres  minor  muscles  insert  on  the 
anterior  surface  of  the  humerus,  they  tend  to  rotate  it  inward  as  well  as  to  adduct  it. 

The  Anterior  Set. 

The  biceps  and  brachialis  anticus  form  the  muscular  mass  on  the  anterior  surface 
of  the  arm. 

The  biceps  has  no  attachment  to  the  humerus.  It  spans  the  bone  and  is 
attached  to  the  scapula  above  and  to  the  radius  and  deep  fascia  of  the  forearm  below. 
In  the  lower  half  of  the  arm  it  lies  on  the  brachialis  anticu.s.  The  long  head  runs 
up  in  the  bicipital  groove,  and  is  covered  by  the  tendon  of  the  pectoralis  major  up  to 
the  tuberosities,  above  that  by  the  transverse  humeral  ligament  up  to  the  capsule, 
which  it  perforates,  and,  crossing  over  the  head  of  the  humerus,  is  attached  to  the 
upper  edge  of  the  rim  of  the  glenoid  cavity  (Fig.  280). 

The  bicipital  branch  of  the  anterior  circumflex  artery  accompanies  the  tendon 
in  the  bicipital  groove.     This  tendon  is  comparati\'elv  rarely  luxated,  because  it  is 


270 


APPLIED    ANATOMY. 


firmly  held  in  place  by  the  transverse  humeral  ligament.  Pus,  in  finding  an  exit 
from  the  joint,  follows  the  long  tendon  of  the  biceps  and  passes  under  the  transverse 
humeral  ligament,  then  beneath  the  tendon  of  the  pectoralis  major  to  appear  on  the 
anterior  aspect  of  the  arm  at  its  lower  border.  Luxation  of  the  tendon  outwardly 
would  be  opposed  bv  the  insertion  of  the  pectoralis  major,  therefore  it  is  only  dis- 
placed inwardlv.  Rupture  of  the  long  tendon  may  occur  from  violent  muscular  con- 
traction; or,  in  rheumatoid  arthritis  of  the  shoulder,  the  tendon  may  become  partly 
dissoh-ed  and  break.  When  this  occurs  the  belly  of  the  muscle  contracts  and  forms 
a  large  protuberance  on  the  front  of  the  arm  (Fig.  2S1). 

The  short  head   of  the  biceps  fuses  with   the    coracobrachiahs  muscle,  to  be 
attached  with  it  to  the  coracoid  process  on  its  outer  portion.     The  pectoralis  minor  is 

the  third  muscle  attached  to  this  process. 
The  biceps  forms  the  large  muscular 
swell  on  the  front  of  the  arm  between 
the  anterior  fold  of  the  axilla  and  elbow. 
At  its  lower  end  the  biceps  inserts  by  a 
strong  tendon  into  the  posterior  border 
of  the  bicipital  tubercle  of  the  radius. ' 
An  example  of  its  rupture  is  shown  in 
Fig.  282.  Between  it  and  the  bone  is 
a  bursa,  which  does  not  communicate 
with  the  elbo^\•-joint.  The  bicipital  fas- 
cia is  given  oft"  from  the  tendon  and 
passes  downward  and  inward  to  blend 
with  the  deep  fascia  co\'ering  the  flexor 
group  of  muscles.  The  biceps  not  only 
flexes  the  radius  on  the  arm  but  also  acts 
as  a  powerful  supinator. 

The  brachialis  anticus  coxers 
the  lower  three-fifths  of  the  humerus 
and  begins  with  X\\o  slips,  one  on  each 
side  of  the  insertion  of  the  deltoid  ten- 
don. It  inserts  into  the  inner  and  lower 
part  of  the  anterior  surface  of  the  coro- 
noid  process  of  the  ulna.  As  the  articu- 
lation of  the  ulna  and  trochlear  surface 
of  the  humerus  is  a  pure  hinge-joint  the 
muscle  acts  solely  as  a  flexor. 


<^' 


Fig.  282. — Rupture  of  the  lower  tendon  of  the  biceps, 
ntraction  of  the  muscle  produces  a  swellii 
high  up  on  the  arm.     (From  a  photograph.) 


The  Posterior  or  Extensor  Set. 
The  posterior  or  extensor  set  in- 


when  present  as  a  distinct  muscle. 

The  Triceps  Muscle. — The  mus- 
cular mass  on  the  posterior  surface  of  the  arm  is  formed  solely  by  the  triceps  muscle. 
It  aiises  by  three  heads  and  inserts  by  a  single  tendon  into  the  olecranon  process  of 
the  ulna.  Its  three  heads  are  the  long,  external,  and  internal.  The  long  head  arises 
from  the  lower  edge  of  the  glenoid  cavity  and  the  scapular  border  below  it  for  2.5 
cm.  (i  in.).  It  blends  with  the  capsule  of  the  joint  and  tends  to  strengthen  it  at 
this  point.  When  the  arm  is  abducted,  this  tendon  is  closely  applied  to  the  capsule 
and  head  of  the  humerus,  and  when  the  head  escapes  in  luxation,  it  slips  out  anterior 
to  the  tendon.  The  external  head  arises  from  the  humerus  above  the  musculospiral 
groove  and  from  the  external  intermuscular  septum ;  the  internal  head  arises  from 
the  humerus  below  the  musculospiral  groove  and  from  the  internal  and  the  lower 
part  of  the  external  intermuscular  septum  (Fig.  283). 

At  its  lower  end  the  triceps  inserts  into  the  olecranon  process,  the  upper  third 
of  the  ulna,  and  the  deep  fascia  of  the  back  of  the  forearm.  The  expansion  of  fascia 
from  the  olecranon  on  the  inner  side  is  thin  and  insignificant,  but  that  on  the  outer 
side,  on  the  contran,-,  is  thick  and  strong,  and  when  fracture  of  the  bone  occurs  is  an 
important  factor  in  pre\-enting  separation  of  the  fragments. 


THE   ARM. 


271 


THE  INTERMUSCULAR  SEPTA. 

The  deep  fascia  of  the  arm  completely  eijcircles  it,  like  a  tube.  It  is  continuous 
above  with  the  fascia  covering  the  deltoid,  pectoralis  major  and  teres  major  muscles, 
and  axillary  fascia.  Below,  it  is  continuous  with  the  fascia  of  the  forearm  and  is 
attached  to  the  olecranon  and  internal  and  external  condyles. 

On  each  side  of  the  lower  half  of  the  humerus,  extending  from  the  condyles  and 
the  bone  above  outward  to  the  deep  fascia,  are  two  fibrous  partitions.  They  are 
the  internal  and  external  intermuscular 
septa.  The  space  in  front  of  them  is  filled 
by  the  flexors,  the  biceps,  and  brachialis 
anticus,  and  the  space  behind  contains 
the  triceps  extensor.  The  external  sep- 
tum begins  at  the  external  condyle  and 
extends  above  to  the  tendon  of  the  del- 
toid, with  which  it  blends.  The  internal 
septum  begins  below  at  the  internal  con- 
dyle and  extends  above  to  the  coraco- 
brachialis.  The  radial  (musculospiral) 
nerve  and  anterior  terminal  branch  of 
the  (superior)  profunda  artery,  as  they 
wind  around  the  humerus  below  the  in- 
sertion of  the  deltoid,  pierce  the  external 
septum.  The  internal  septum  is  pierced 
high  up  by  the  ulnar  nerve  and  superior 
ulnar  collateral  (inferior  profunda)  artery 
as  they  emerge  at  about  the  level  of  the 
lower  portion  of  the  insertion  of  the 
coracobrachialis  to  pass  down  behind 
the  internal  condyle. 

These  intermuscular  septa  are  of 
importance  in  operative  procedvu'es  be- 
cause they  indicate  the  limits  of  the  mus- 
cles and  position  of  nerves  and  vessels. 

SURFACE  ANATOMY. 
Inasmuch  as  the  movements  of  the 
elbow-joint  are  anteroposterior  only  and 
not  lateral,  the  muscles  are  principally 
on  the  front  and  back  and  not  on  the 
sides.  Hence  on  looking  at  an  arm 
a  rounded  mass  is  seen  anteriorly  and 
posteriorly,  and  separating  them  on  the 
sides  can  be  seen  in  a  spare,  muscular 
individual,  distinct  furrows  called  the 
internal  ■axidi  external  bicipital  furrows. 
If  these  furrows  are  obscured  by  fat, 
one  can  still  feel  that  the  bone  is  nearer 
the  surface  at  these  points  than  else- 
where. The  anterior  muscle  mass  is 
formed   by   the   biceps    and    brachialis 

anticus  muscles,  the  posterior  mass  by  the  triceps.  The  bone  is  most  readily 
felt  at  the  insertion  of  the  deltoid  at  the  middle  of  the  outer  side  of  the  arm. 
From  this  point  directly  down  to  the  external  condyle  passes  the  external  inter- 
muscular septum  and  external  bicipital  furrow.  Winding  around  from  the  poste- 
rior edge  of  the  insertion  of  the  deltoid  is  the  radial  {musculospiral )  nerve  and 
{superior')  profunda  artery.  They  pierce  the  external  intermuscular  septum  and 
pass  downward  in  the  groove  formed  by  the  brachioradialis  (supinator  longus)  and 
extensor  muscles  on  the  outside  and  the  brachialis  anticus  on  the  inside.  On  the 
inner  side  of  the  arm  the  bicipital  furrow,  between  the  biceps  in  front  and  the  triceps 


Fig.  2S3. — Triceps  and  anconeus  muscles. 


272 


APPLIED    x\NATOMY. 


behind,  is  quite  evident  and  marks  the  internal  intermuscular  septum,  which  extends 
to  the  medial  (internal)  condyle.  In  front  of  it  lie  the  brachial  artery  and  veins, 
and  median  and  viedial  antebrachial  {internal)  cutaneous  nerve.  At  the  upper 
portion  of  the  inside  of  the  arm  can  be  seen  the  swell  formed  by  the  coracobrachialis 
muscle.  The  inner  or  posterior  border  of  the  coracobrachialis  is  continuous  with 
the  inner  border  of  the  biceps,  and  the  brachial  artery  follows  them.  The  coraco- 
brachialis muscle  ends  just  below  the  level  of  the  insertion  of  the  deltoid,  and,  of 
course,  can  neither  be  seen  nor  felt  below  that  point.  It  is  here  that  the  ulnar  nerve 
leaves  the  artery  to  pierce  the  internal  intermuscular  septum  in  company  with  the 
superior  ulnar  collateral  (inferior profunda)  artery  to  reach  the  groove  behind  the 
internal  condyle.  The  brachial  artery  is  covered  only  by  the  skin  and  superficial  and 
deep  fascia,  and  can  be  felt  pulsating  along  the  inner  edge  of  the  biceps  muscle  and 
tendon;  it  can  be  compressed  against  the  bone  by  pressure  directed  outwardly 
above  and  inclining  more  posteriorly  as  the  artery  progresses  down  toward  the  bend 
of  the  elbow.  It  is  on  the  inner  side  of  the  arm  in  the  upper  two-thirds,  and  is  more 
anterior  in  the  lower  one-third  (  Fig.  284). 

The  cephalic  vein  runs  up  the  external  bicipital  furrow  and  the  basilic  up  the 
internal.  At  the  junction  of  the  middle  and  lower  thirds  of  the  arm  the  basilic' 
pierces  the  deep  fascia  and  from  that  point  runs  up  beneath  it  and  joins  with  the 
internal  vena  comes  opposite  the  lower  border  of  the  teres  major  or  subscapularis. 

THE  BRACHIAL  ARTERY. 

The  arm  being  abducted,  the  course  of  the  brachial  artery  is  indicated  by  a 
line  drawn  from  the  inner  edge  of  the  coracobrachialis  muscle,  at  the  junction  of 
the  anterior  and  middle  thirds  of  the  axilla,  above,  to  a  point  just  inside  the  tendon 
of  the  biceps  at  the  bend  of  the  elbow,  below,  midway  between  the  two  condyles 
of  the  humerus.  This  lies  in  the  internal  bicipital  furrow  along  the  inner  edge  of 
the  biceps  muscle.  The  artery  is  superficial  in  its  entire  course.  It  is  accom- 
panied by  two  small  venae  comites,  which  closely  embrace  it.  The  basilic  vein 
runs  along  its  inner  side.  The  median  nerve  lies  on  the  artery  to  its  outer  side 
above,  then  directly  on  it  and  a  httle  to  its  inner  side  at  the  middle,  and  passes 
to  its  inner  side  at  the  bend  of  the  elbow.  The  medial  antebrachial  (internal) 
cutaneous  nerve,  much  smaller  than  the  median,  passes  down  along  the  inner  side 
of  the  artery  between  it  and  the  basilic  vein  to  pierce  the  fascia  about  the  middle  of 
the  arm  (Fig.  285). 

The  ulnar  nerve  lies  to  the  inner  side  of  the  artery  above  and  is  posterior  to  the 
basilic  vein.  About  opposite  the  insertion  of  the  coracobrachialis  it  diverges  from 
the  artery  to  pierce  the  internal  intermuscular  septum. 


Relations  of  the  Br,\chial  Artery 

In  Front. 
Skin  and  fascia 

Overlapped  by  coracobrachialis  and  biceps 
Median  basilic  vein 
Bicipital  fascia 
Median  nerve 


Outer  Side 

Inner  Side 

Median  nerve,  above 

Medial  antebrachial  (int.) 

Coracobrachialis 

Brachial 

cutaneous  and 

Biceps 

Artery 

ulnar  nerves 

Vena  conies 

Median  nerve  below 
Basilic  vein 
Vena  comes 

Behind 
Triceps  (long  and  inner  heads) 
Radial  (musculospiral)  nerve 
(Sup.)  profunda  artery 
Coracobrachialis  muscle 
Brachialis  anticiis  muscle 


THE  ARM. 


273 


Branches  of  the  Brachial  Artery. — The  branches  of  the  brachial  artery  are 
the  profunda  (superior),  the  superior  uhiar  collateral  (inferior  profunda),  the  nutrient, 
muscular,  and  inferior  ulnar  collateral  (anastomotica  magna;. 


Supinators  and  extensors 


>%ijujipiii    • 


nd  flexors 

Internal  bicipital  furrow 

Triceps,  long  and  inner  heads 

Brachial  artery 

Coracobrachialis  muscle 
Fig.  284- — Surface  anatomy  of  the  arm, 


Not  infrequently  the  brachial  artery  instead  of  dividing  into  the  radial  and  ulnar 
opposite  the  neck  of  the  radius  divides  higher  up.  This  is  called  a  high  division  and 
is  seen  most  often  in  the  upper  third  of  the  arm.      The  two  vessels  may  follow  the 


Musculocutaneous  nerve 


Anastomotica  magna  artery 


Superior  profunda  artery 
Musculospiral  nerve 
Inner  head  of  triceps 
Ulnar  nerve 
Inferior  profunda  artery 


Basilic  vein 

Fig.  285. — Dissection  of  the  arm,  viewed  from  the  inner  side. 

usual  course  in  the  arm,  or  the  radial  may  run  under  the  biceps  tendon,  instead  of 
over  it,  and  the  ulnar  may  accompany  the  median  nerve  in  front  of  the  medial  con- 
dyle or  the  ulnar  nerve  behind  it. 


274 


APPLIED    ANATOMY. 


The  pi-qfunda  is  given  ofE  just  below  the  lower  edge  of  the  posterior  fold  of  the 
axilla  (teres  major).  It  accompanies  the  radial  (musculospiral)  nerve  around  the 
arm  to  its  outer  side;    it  sends  one  branch,  the  radial  collateral,  to  the  front  of  the 


Median  nerve 
Biceps  muscle 


Fig.  286. — Ligatii 


1  of  the  brachial  artery  in  the 
and  the  ul 


liddle  of  the  arm  showing  the  ] 
■  nerve  to  its  inner  side. 


the  artery- 


da  (A.  profunda 


Inferior  profunda  (collateralis 
ulnaris  superior) 


elbow  and  the  middle  collateral  behind  it.      The   superior  ulnar  collateral  artery 
(inferior  profunda)  comes  oil  about  opposite  the  insertion  of  the  coracobrachialis 

muscle.  It  is  much  smaller  than  the  pro- 
funda and  with  the  ulnar  nerve  pierces  the 
internal  intermuscular  septum.  The  7ititri- 
C7it  artery  comes  off  close  to  the  origin  of 
the  superior  ulnar  collateral  (inferior  pro- 
funda) or  is  a  branch  of  it.  It  passes  down- 
ward in  the  bone  in  a  direction  toward  the 
elbow-joint.  The  ijiferior  idnar  collateral 
(anastomotica  magna)  is  given  off  5  cm. 
(2  in.)  above  the  elbow  and  passes  inward 
over  the  brachialis  anticus  to  divide  into 
two  branches,  one  going  down  in  front  and 
the  other  behind  the  elbow. 

Ligation  of  the  Brachial  Artery. 
— In  ligating  the  brachial  arter}'.  Heath 
strongly  advises  that  the  arm  be  held  by  an 
assistant  in  an  abducted  position  with  the 
hand  supine  and  not  allowed  to  rest  on  any- 
thing. The  object  of  this  is  to  avoid  hav- 
ing the  artery  overlapped  by  the  triceps  be- 
ing pushed  up  and  thus  becoming  obscured. 
The  incision  is  to  be  made  in  the  line 
from  the  inner  edge  of  the  coracobrachialis 
to  a  point  midway  between  the  tips  of  the 
condyles.  The  deep  fascia  is  to  be  opened 
and  the  inner  edge  of  the  biceps  muscle 
is  to  be  sought  for,  recognized,  and  held 
outward.  The  pulsation  of  the  artery  may 
indicate  its  position  in  the  living;  if  not,  it 
is  to  be  sought  for  to  the  inner  side  of  the 
edge  of  the  biceps.  The  median  nerve  is 
not  to  be  mistaken  for  it.  It  will  lie  either 
over  its  middle  or  to  its  inner  side  if  low  down  and  to  its  outer  side  if  high  up  (Fig.  286). 
The  ulnar  nerve  lies  on  the  inner  side  of  the  artery  as  far  as  the  middle  of  the 


Fig.  287. — Collateral  circulation  after  ligation  of  the 
brachial  artery  at  the  bend  of  the  elbow. 


THE  ARM.  27s 

arm,  it  then  leaves  the  artery.  Below  the  middle,  if  the  search  is  made  too  far 
posteriorly,  the  ulnar  nerve  and  basilic  vein  will  be  encountered.  The  ulnar  nerve 
should  not  be  seen,  the  basilic  vein  and  median  nerve — and  above  the  middle  of  the 
arm  the  medial  antebrachial  (internal)  cutaneous  nerve — are  to  be  displaced  to  the 
inner  side. 

The  needle  is  to  be  passed  from  within  outward.  Care  must  be  taken  not  to 
mistake  a  large  superior  or  inferior  profunda  for  the  main  trunk.  A  high  division 
of  the  brachial  may  give  two  vessels  of  approximately  equal  size.  Of  course,  in  such 
a  case  both  must  be  ligated. 

Collateral  Circulation. — If  the  ligature  is  placed  above  the  profunda  (superior) 
branch,  the  anterior  and  posterior  circumflex  will  anastomose  with  the  profunda 
(superior)  and  superior  ulnar  collateral  (inferior  profunda)  below.  If  the  ligature  is 
placed  between  the  profunda  and  superior  ulnar  collateral  arteries,  the  profunda 
(superior)  will  anastomose  below  with  the  radial  recurrent  and  posterior  interosseous 
recurrent  on  the  outer  side  and  will  also  communicate  with  the  inferior  ulnar 
collateral  (anastomotica  magna)  and  superior  ulnar  collateral  (inferior  profunda) 
on  the  inside  (Fig. 287).  If  below  the  superior  ulnar  collateral  (inferior  profunda) 
then  the  profunda  (superior)  would  anastomose  with  the  radial  and  posterior  inter- 
osseous recurrents  on  the  outside,  and  the  superior  ulnar  collateral  (inferior  profunda) 
with  the  inferior  ulnar  collateral  (anastomotica  magna)  and  the  anterior  and  posterior 
ulnar  recurrents. 

AMPUTATION    OF    THE    ARM. 

In  amputation  one  has  to  deal  with  a  part  of  the  body  that  is  approximately 
cylindrical  in  shape  and  that  contains  only  a  single  bone  entirely  surrounded  by 
soft  parts.  The  circular  method  is  more  applicable  to  amputation  of  the  arm  below 
the  insertion  of  the  deltoid  than  to  any  other  part  of  the  body,  but  nevertheless  in 
some  cases,  particularly  in  muscular  arms,  difficulty  may  be  experienced  in  turning 
back  the  cuff.  In  such  cases  the  cuf?  is  slit  by  the  surgeon  and  the  operation 
becomes  one  of  square  skin  flaps.  F"or  this  reason  flap  amputations  are  usually  to 
be  preferred. 

The  arm  may  be  amputated  at  any  place,  high  up  or  low  down.  Artificial 
appliances  for  the  upper  extremity  are  comparatively  useless;  hence  the  height  of 
division  of  the  bone  is  determined  by  the  injury. 

As  it  is  desirable  to  retain  the  head  of  the  bone  and  tuberosities,  if  pos- 
sible, in  order  to  preserve  the  shape  of  the  shoulder  and  retain  the  attachment 
of  the  muscles,  amputation  may  be  done  through  the  surgical  neck.  This  is  just 
below  the  epiphyseal  line.  In  performing  a  flap  amputation  the  soft  parts  should 
cover  or  cap  the  bone  like  a  hemisphere:  therefore  the  total  length  of  the  flaps  should 
be  equal  to  one-half  the  circumference  of  a  sphere  whose  diameter  is  the  diameter  of 
the  limb  at  the  point  of  section  of  the  bone.  If  the  diameter  of  the  limb  is  4  inches, 
then  the  total  length  of  the  flaps  should  be  approximately  6  inches.  If  the  flaps 
were  of  equal  length  then  each  would  be  3  inches  long.  If  there  was  only  one  flap, 
it  would  be  6  inches  long. 

It  is  an  axiom  in  surgery  that  in  flap  amputations  the  artery  should  be  contained 
in  the  shorter  flap.  The  operator  should  accurately  know  the  course  of  the  artery 
and  avoid  making  his  flaps  in  such  a  manner  as  to  bring  the  vessel  in  the  angle  of  the 
wound.  Otherwise  the  artery  is  liable  to  be  split.  In  a  high  amputation  the 
external  flap  may  be  long  and  the  internal  short.  In  the  middle  of  the  arm  antero- 
posterior flaps  are  preferred  and  the  artery  is  included  in  the  posterior  flap.  If  the 
amputation  is  in  the  lower  third  and  the  flaps  are  anteroposterior,  then  the  artery  of 
necessity  is  in  the  anterior  flap. 

Above  the  middle  of  the  arm  the  deltoid,  coracobrachialis,  and  biceps  muscles 
are  free  and  therefore  retract  markedly  when  cut.  In  the  middle  the  biceps  only  is 
free  and  the  same  is  the  case  in  the  lower  third.  The  triceps  and  brachialis  anticus 
are  attached  to  the  bone  and  therefore  retract  but  little  when  cut.  Surgeons  have 
called  attention  to  the  necessity  of  being  careful  to  see  that  the  radial  (musculospiral) 
nerve  is  properly  divided,  otherwise  it  may  be  torn  by  the  saw.     The  groove  in  which 


276 


APPLIED    ANATOMY. 


it  lies  may  be  unusually  deep  and  necessitate  a  special  effort  to  divide  it.  On  the  face 
of  the  stump  the  artery  is  to  be  looked  for  to  the  inner  side  of  the  bone  in  the  upper 
two-thirds  of  the  arm  and  anteriorly  in  the  lower  third.  Lying  on  it  will  be  the 
median  ner\-e  and  to  its  inner  side  the  ulnar  nerve.  At  the  level  of  the  insertion  of 
the  deltoid  the  radial  (musculospiral)  ner\-e,  accompanied  by  the  (superior)  profunda 
artery,  will  be  posterior  or  toward  the  outer  side.  The  superior  ulnar  collateral  (in- 
ferior profunda)  arterj-  is  given  off  at  the  level  of  the  insertion  of  the  coracobrachialis 
muscle,  which  is  about  opposite  the  insertion  of  the  deltoid.  It  accompanies  the  ulnar 
nerve.  A  nerve  mav  be  seen  Iving  between  the  biceps  and  brachialis  anticus.  It  is  the 
musculocutaneous  which  becomes  superficial  just  above  the  bend  of  the  elbow  (Fig.  288) . 


Median  nerve 

Brachial  artery- 
Internal  cutaneous  nerve  , 

Ulnar  nerve  and  inferior, 
profunda  arterj' 


Coraco-brachiaV 


Biceps 
Musculocutaneous  nerve 


Fig.  288. — Amputation  just  above  the  middle  of  the  arm. 

Five  cm.  (2in. )  above  the  elbow  the  inferior  ulnar  collateral  (anastomotica 
magna )  artery  may  be  expected  to  be  encountered  passing  down  and  in  over  the 
brachialis  anticus  muscle. 

FRACTURES    OF    THE    HUMERUS. 

Fractures  of  the  Shaft  of  the  Humerus. — There  seems  to  be  but  little  doubt 
that  in  many  cases  the  character  of  displacement  of  the  fragments  in  fracture  of  the 
shaft  of  the  humerus  is  due  to  the  mode  of  injury  and  not  to  muscular  action.  This 
being  so  accounts  for  there  being  less  uniformity  in  these  fractures  than  in  those 
higher  up,  which  have  already  been  considered.  There  are  some  cases,  however,  in 
which  muscular  action  does  play  a  part  and  the  possible  influence  of  the  muscles 
should  be  understood. 

The  line  of  fracture  is  usually  more  or  less  oblique,  in  rare  cases  nearly  trans- 
verse, but  the  displacement  is  often  not  marked.  Notwithstanding  this  latter  fact, 
non-union  of  fracture  of  the  shaft  of  the  humerus  is  one  of  the  most  frequent  of  any 
in  the  body. 

Muscular  action  shows  its  influence  most  markedly  in  producing  displacements 
in  three  directions,  viz. ,  in  towards  the  body,  out  away  from  the  body,  and  direcdy 
anteriorly. 


THE   ARM. 


277 


There  are  two  main  points  where  fracture  occurs;  immediately  above  the  inser- 
tion of  the  deltoid  and  below  it. 

Fracture  above  the  Insertion  of  the  Deltoid. — The  bone  may  be  fractured  imme- 
diately above  the  deltoid  insertion.  In  this  case  the  powerful  axillary  fold  muscles, 
pectoralis  major,  teres  major,  and  latissimus  dorsi,  being  attached  to  the  upper  frag- 
ment, tend  to  draw  it  toward  the  body,  while  the  deltoid  tends  to  draw  the  lower 
fragment  out.  The  influence  of  the  other  muscles,  biceps,  coracobrachialis,  and  triceps, 
would  be  to  increase  the  overlapping  (Fig.  289). 

Fracture  below  the  Deltoid  Insertion. — This  is  the  more  common  site  of  fracture. 
The  line  of  fracture  is  most  apt  to  be  from  abo^'e  downward  and  outward.  The 
upper  fragment  is  displaced  anteriorly  by  the  coracobrachialis  and  anterior  portion 


Pectoralis  major 


Fig.  289. — Fracture  of  the  shaft  of  the  humerus  just  above  the  insertion  of  the  deltoid  and  below  the  inser- 
tion of  the  axillary  fold  muscles.  The  lower  fragment  is  seen  to  be  drawn  outward  by  the  deltoid :  the  upper  frag- 
ment is  seen  to  be  drawn  inward  by  the  pectoralis  major,  latissimus  dorsi,  and  teres  major. 


of  the  deltoid  and  is  drawn  outward  by  the  deltoid  aided  by  the  supraspinatus.  To 
relax  the  deltoid  the  arm  is  sometimes  dressed  in  an  abducted  position  (Fig.  290). 

Non-Unio7i. — The  humerus  has  muscles  attached  to  it  almost  throughout  its 
entire  length,  and  when  the  sharp  ends  of  the  fragments  are  displaced  they  probably 
become  fi.xed  in  the  surrounding  muscle,  and  proper  apposition  of  the  fragments  is 
prevented,  hence  non-union.  Hamilton  believed  that  lack  of  proper  fixation  was  also 
a  prominent  cause. 

The  Radial  (Musculospiral)  Nerve. — In  fracture  of  the  shaft  of  the 
humerus,  paralysis  of  the  extensors  due  to  injury  of  the  radial  nerve  is  compara- 
tively common.  It  also  occurs  from  pressure  due  to  the  use  of  crutches,  to  sleep- 
ing:   on   the  arm,  etc.      The  other  nerves   are  too    far  removed  from  the  bone    to 


278 


APPLIED    ANATOMY. 


be  injured,  but  the  radial  (musculospiral)  lies  on  the  bone  in  the  radial  (musculo- 
spiral)  groove  in  approximately  the  middle  third  of  the  bone.  It  comes  into  contact 
with  the  bone  posteriorly  above  the  insertion  of  the  deltoid  and  leaves  the  bone  on 
its  outer  anterior  surface  to  pass  between  the  brachialis  anticus  and  brachioradialis 
(supinator  longus)muscles.  Paralysis  may  be  caused  (i)  by  direct  injury  to  the 
nerve  at  the  time  the  fracture  is  received.  (2)  By  subsequent  changes  in  the  nerve 
due  to  its  being  stretched  over  the  sharp  edge  of  a  fragment.  (3)  Bv  being  included  in 
callus.  The  last  is  probably  much  more  rarely  the  case  than  the  two  former  (Fig.  291). 
Paralysis  should  be  examined  for  early  in  the  course  of  treatment.  Too  often  it 
is  detected  only  after  the  splints  have  been  removed,  and  then  it  is  apt  to  be  ascribed 
to  improper  treatment  or  to  misapplied  pressure.     The  symptoms  of  involvement  of 


Fig.  290. — Posterior  view  of  a  fracture  of  the   shaft  of  the  humerus   just   below  the  Insertion  of  the   deltoid, 
showing  the  influence  of  that  muscle  in  producing  abduction  of  the  upper  fragment. 

the  musculospiral  nerve  are  wrist-drop  and  diminution  of  the  power  of  supination, 
also  some  sensory  changes  in  the  dorsum  of  the  hand  and  forearm. 

This  nerve  is  frequently  paralyzed  from  pressure  in  cases  in  which  there  is  no 
fracture,  as  from  sleeping  on  the  arm,  the  use  of  crutches,  and  also  in  certain  sys- 
temic aflections,  such  as  lead  poisoning.  It  supplies  the  triceps,  part  of  the  brachialis 
anticus,  brachioradialis  (supinator  longus),  and  extensor  carpi  radialis  longior 
muscles  in  the  arm,  and  then  proceeds  to  the  forearm.  The  branch  to  the  triceps  is 
given  off  before  the  nerve  enters  the  musculospiral  groove,  hence  is  not  often  injured, 
and  loss  of  extension  of  the  forearm  is  not  often  present;  even  paralysis  of  the  other 
muscles  mentioned  is  not  common,  the  forearm  muscles  being  mostly  affected.  The 
branch  to  the  inner  head  of  the  triceps  also  supplies  the  anconeus. 


THE  ARM. 


279 


OPERATIONS    ON    THE   ARM. 
Caries  or  necrosis  of  the  humerus  may  necessitate  operative  interference  at  almost 
any  part  of  the  arm.     The  same  may  be  said  of  wounds.      In  operative  procedures 
it  is  sometimes  desirable  to  avoid  important  structures  and  at  others  to  find  them. 


Long  head  of  triceps 


Outer  head  of  triceps 
,    / jff  Radial  (musculospiral)  nerve 

Superior  profunda  artery' 

Brachioradialis 

Extensor  carpi  radialis  longio 

Extensor  muscles  of  forearm 
External  condyle 


yi 


-The  radial  (muscalospiral)  nerve  and  outer  side  of  arm. 


The  important  structures  run  lengthwise,  hence  transverse  incisions  are  not  to  be 
used.  Most  of  the  large  vessels  and  nerves  pass  down  the  inner  side  of  the  arm, 
hence  this  region  is  usually  avoided.  The  bone  can  readily  be  reached  by  an  incision 
downward  from  the  insertion  of  the  deltoid,  but  no  operation  is  to  be  done  in  this 
region  without  a  thorough  familiarity  with  the  course  of  the  musculospiral  nerve. 


28o  APPLIED    ANATOMY. 

A  line  drawn  on  the  posterior  surface  of  the  arm  from  behind  and  above  the  insertion 
of  the  deltoid  to  the  groo\-e  on  the  anterior  surface  between  the  brachialis  anticus  and 
brachioradialis  (supinator  longus)  just  above  and  to  the  inner  side  of  the  external 
condyle  will  indicate  its  course.  If  exposed  during  an  operation  bleeding  from  the 
accompanj-ing  (superior)  profunda  artery  may  be  expected.  The  median  and  ulnar 
nen-es  give  off  no  branches  in  the  upper  arm.  The  median  can  be  readily  located 
by  its  relation  to  the  artery.  It  lies  to  the  outer  and  anterior  side  of  the  brachial 
arter)'  above,  then  in  front,  and  then  to  its  inner  side  below.  The  ulnar  nei-ve  lies 
to  the  inner  side  of  the  artery  and  between  it  and  the  -s-ein  posteriorly.  In  the  middle 
of  the  arm,  it  leaves  it  to  pierce  and  pass  beneath  the  internal  intermuscular  septum 
and  thence  behind  the  medial  (internal)  condyle.  Operations  involving  it  would 
be  accompanied  by  bleeding  from  its  companion  the  superior  ulnar  collateral  arterj- 
(inferior  profunda). 

In  operations  on  the  lower  portion  of  the  bone  the  position  of  the  inferior  ulnar 
collateral  (anastomotica  magna),  5  cm.  (2  in.)  above  the  elbow,  should  be  borne  in 
mind.  It  runs  on  the  brachialis  anticus  muscle  and  tow-ards  the  inner  and  not  the 
outer  side.  Incisions  on  the  outer  side  will  encounter  the  cephalic  vein  in  the  external 
bicipital  furrow.  Incisions  on  the  inner  side  will  encounter  the  basilic  vein  :  at  the 
junction  of  the  lower  and  middle  thirds  of  the  arm  it  pierces  the  deep  fascia. 

REGION   OF  THE   ELBOW. 

The  elbow  is  so  named  because  at  this  point  the  arm  is  usually  bent.  A  joint  is 
here  inserted  which  permits  of  flexion  and  extension  ;  when  the  arm  is  fully  extended 
the  ' '  elbow ' '  might  be  said  to  ha\'e  disappeared.  The  lower  end  of  the  humerus 
forms  the  proximal  portion  of  the  joint  and  the  upper  ends  of  the  ulna  and  radius  form 
its  distal  portion.  Ligaments  join  these  bones  together  to  form  the  joint,  and  the 
blood-vessels  and  nerves  change  in  character  in  this  region  as  they  pass  from  the  arm 
to  the  forearm. 

The  bones  are  frequently  subject  to  fractures  which  are  of  an  exceedingly  puz- 
zling and  disabling  character.  The  joint  becomes  luxated  and  the  vessels  and  nerves 
are  not  infrequently  injured.  A  thorough  knowledge  of  the  anatomy  of  the  region 
is  absolutelv  essential  to  the  proper  treatment  of  these  affections. 

BOXES    OF   THE    ELBOW. 

Humerus. — The  lower  end  of  the  humerus  broadens  laterally  and  is  slightly 
concave  on  its  anterior  surface  ;  this  causes  the  articular  surfaces  to  look  downward 
and  forward  and  not  backward.  It  carries  two  articular  surfaces:  one,  the  trochlea,  for 
the  ulna,  and  the  other,  the  capitclhim,  for  the  radius.  The  trochlea,  descending 
lower  than  the  capitellum,  causes  the  line  of  the  joint  to  incline  downward  and  inward 
instead  of  being  direcdy  transverse,  thus  producing  the  ' '  carrying  angle '  (Fig.  294). 
Extending  from  the  edges  of  the  articular  surfaces  outward,  one  on  each  side,  are  the 
condyles,  medial  [vitemaJ)  and  latei-al  ( exterJial ) . 

Chaussier  gave  the  name  epicondyle  to  the  condyles.  He  called  the  medial 
condjrle  the  cpitrochlca  and  the  lateral  (external)  condyle  Xh&  epicondyle.  Henle 
called  the  internal  condyle  the  epicondylus  medialis  and  the  external  condyle  the 
epicondylus  lateralis.  The  name  epicondyle  is  now  quite  generally  employed  by  both 
surgical  and  anatomical  writers  to  designate  the  projecting  extra-articular  portion  of 
the  condyles,  so  that  the  terms  are  practically  synonymous  (Fig.  293). 

From  the  condyles  two  ridges  run  upward.  The  lateral  (external)  supracon- 
dylar 7-idge  is  the  more  marked  of  the  two  and  gi\-es  origin  to  the  brachioradialis 
(supinator  longus)  and  the  extensor  carpi  radialis  longior  muscles,  and  passes 
posterior  to  the  deltoid  eminence  to  be  continuous  with  the  posterior  lip  of  the 
radial  (musculospiral)  groove.  The  medial  (internal')  supracondylar  7-idge  is  much 
less  prominent  than  the  lateral  and  soon  blends  with  the  shaft  of  the  bone.  Above 
the  trochlea  and  capitellum  anteriorly  are  two  fossae,  the  coronoid  and  the  j'adiah 
to  receive  the  coronoid  process  and  head  of  the  radius  when  the  arm  is  in  complete 


REGION    OF   THE    ELBOW.  281 

flexion.  On  the  posterior  surface  there  is  another  depression,  the  olecranon  fossa,  to 
receive  the  olecranon  process  in  extreme  extension.  The  projecting  hook-like  shape 
of  the  median  condyle  causes  it  to  be  more  frequently  fractured  than  the  less  promi- 
nent lateral  condyle.  The  two  condyles  are  readily  felt  directly  beneath  the  skin  and 
are  the  only  points  of  the  humerus  that  are  really  subcutaneous. 

Ulna. — The  upper  extremity  of  the  ulna  articulates  above  with  the  trochlea  of 
the  humerus  and  on  its  outer  side  with  the  radius.  Its  upper  end  is  the  olecranon 
process.  The  posterior  portion  of  this  process  is  called  the  tip  of  the  olecranon  and 
is  continuous  with  the  posterior  surface  of  the  ulna,  which  is  subcutaneous.      Immedi- 


•  of  bones  of  elbow. 


ately  in  front  of  the  olecranon  is  a  large  hollow,  which  receives  the  trochlea.  It  is 
called  the  greater  sigmoid  cavity.  The  anterior  margin  of  the  cavity  is  called  the 
coronoid process.  On  the  outer  side  of  the  coronoid  process  is  a  hollow  called  the 
lesser  sigmoid  cavity,  which  receives  the  head  of  the  radius.  Fracture  of  the  bone 
frequently  occurs  through  the  narrow  portion  of  the  olecranon  process  into  the  greater 
sigmoid  cavity. 

Radius. — The  radius  ends  above  in  a  flat  rounded  head.  The  upper  surface 
of  this  head  articulates  with  the  capitellum.  The  lateral  surface  articulates  internally 
with  the  lesser  sigmoid  cavity  of  the  ulna.  The  remainder  of  the  circumference  of 
the  head  is  embraced  by  the  orbicular  ligament.  Immediately  below  the  head  is  the 
constricted  neck  and  bicipital  tuberosity.  To  the  posterior  half  of  this  latter  the 
tendon  of  the  biceps  is  attached,  but  its  anterior  portion  is  smooth  and  provided  with 
a  bursa.  The  head  of  the  radius  is  subcutaneous  posteriorly,  but  the  rest  is  too  much 
covered  by  muscles  to  be  readily  palpated. 


APPLIED    ANATOMY. 


ELBOW-JOINT. 

By  the  term  elbow-joint  is  meant  the  articulation  between  the  humerus  above 
and  the  ulna  and  upper  surface  of  the  radius  below.  The  articulation  between  the 
upper  end  of  the  radius  and  the  ulna  forms  the  superior  radio-ulnar  artiadation  and 
does  not  belong  to  the  elbow-joint  proper.  As  has  already  been  pointed  out,  the 
ulna  articulates  with  the  trochlea  and  the  radius  with  the  capitellum. 

The  elbow-joint  is  a  pure  hinge-joint.  The  articulation  between  the  trochlea 
and  ulna  is  so  shaped  as  to  allow  no  lateral  motion,  but  only  an  anteroposterior  one. 
The  articulation  between  the  capitellum  and  upper  surface  of  the  head  of  the  radius 

is,  on  the  contrary,  a  ball-and-socket  joint.      The 
socket,  it    is  true,  is   shallow,   but   it   is   perfectly 
i  spherical,  made  so  by  the  rotary  movement  of  the 

radius  in  pronation  and  supination.  Hence  it  fol- 
lows that  the  shape  and  continuity  of  the  upper  ex- 
tremity depends  upon  the  articulation  of  the  ulna 
with  the  humerus:  it  further  follows  that  if  the 
radius  be  removed  from  the  elbow -joint  the  forearm 
would  still  be  held  in  its  proper  relation  to  the  arm, 
but  if  the  ulna  be  removed  the  stability  of  the  joint 
would  be  lost  and  the  forearm  would  move  in  any 
direction,  laterally  as  well  as  anteroposteriorly.  It 
is  for  this  reason  that  injuries  involving  the  medial 
condyle  and  trochlea  are  more  liable  to  be  followed 
by  serious  disability  than  are  those  of  the  lateral 
condyle  and  capitellum. 

The  movement  of  the  joint  takes  place  around 
a  transverse  a.xis,  which  passes  from  side  to  side 
below  and  in  front  of  the  condyles.  The  forearm 
can  be  extended  to  an  angle  of  iSo  degrees,  or  a 
straight  line,  with  the  arm.  It  can  be  fle.xed  to  an 
angle  of  30  to  40  degrees.  Sometimes  it  cannot  be 
fle.xed  so  much,  so  that  if  after  an  injury  to  the 
joint  the  patient  can  flex  the  elbow  to  half  a  right 
angle,  or  45  degrees,  he  may  be  regarded  as  hav- 
ing regained  a  normal  amount  of  motion. 

Carrying  Angle. — The  axis  of  motion  of  the 
joint  is  not  e.xacdy  transverse,  but  slopes  slightly 
from  the  outside  downward  and  inward.  The 
effect  of  this  is  to  give  a  slight  obliquity  to  the 
motions  of  fle.xion  and  extension.  This  obliquity 
is  not  noticeable  except  in  extreme  e.xtension  and 
flexion.  When  the  forearm  is  completely  extended 
=d  it  is  seen  to  lie  not  in  the  axis  of  the  arm  but  to 
bend  outward  from  the  elbow  at  an  angle  of  170 
degrees.  This  angle  is  called  the  ' '  carrying  angle, ' ' 
because  by  resting  the  elbow  against  the  side,  any  article  which  is  carried  in  the  ex- 
tended hand  is  kept  away  from  the  body.  Sometimes  the  line  of  the  forearm  is  almost 
straight  with  that  of  the  arm,  at  others  the  deflection  may  amount  to  15  degrees.  It 
may  vary  on  the  two  sides  and  10  degrees  may  be  considered  an  average;  Woolsey 
gives  6  degrees  as  the  average.  This  carrying  angle  becomes  lost  in  certain  cases  of 
fracture  of  the  elbow,  as  will  be  pointed  out  later.  As  the  elbow  is  flexed  the  carrying 
angle  disappears  (see  Fig.  294). 

When  flexion  is  complete  the  ulna  instead  of  coming  up  toward  the  head  of  the 
humerus  inclines  inward  at  an  angle  of  10  degrees.  Morris  states  that  the  hand  has 
a  tendency  to  point  to  the  middle  of  the  clavicle,  which  would  make  an  angle  of  20 
degrees.      This  we  believe  to  be  too  great. 


Fig.  294. — The  carrying  angl 
by  the  deviation  outward  of  the  a 
forearm  from  the  a.xis  of  the  arm. 


REGION    OF    THE    ELBOW. 


283 


LIGAMENTS    OF   THE    ELBOW. 

The  ligaments  of  the  elbow-joint  are  four  in  number — anterior,  posterior,  internal 
lateral,  and  external  lateral. 

In  all  joints  there  are  two  kinds  of  ligaments.  One  kind  serves  to  retain  the 
synovial  fluid;  it  is  a  capsular  ligament  and  is  usually  thin;  the  other  kind  is  thick, 
firm,  and  strong,  and  is  intended  to  bind  the  bones  together  and  prevent  their  dis- 
placement and  to  limit  movement.  These  two  kinds  of  ligaments  often  blend 
together  so  that  it  is  impossible  to  say  where  one  begins  and  the  other  ends ;  at  other 
places  they  are  quite  distinct.  If  an  elbow-joint  is  distended  with  effusion  (or  wax) 
the  distinction  is  readily  seen.  The  capsule  becomes  distended  in  front  and  behind, 
while  at  the  sides  the  ligaments  remain  closely  applied  to  the  bones;  hence  we  learn 
that  the  anterior  and  posterior  ligaments  are  capsular  in  their  function  while  the 
lateral  ligaments  are  retentive.      These  will  be  considered  more  in  detail  later. 

Superior  Radio-ubiar  Articulation. — While  the  superior  radio-ulnar  articula- 
tion is  not  considered  a  part  of  the  elbow-joint  proper,  it  is  nevertheless  so  closely 


Fig.  295. — ^The  external  lateral  ligament  of  the  elbow- joint,  showing  its  A  shape.  Its  upper  end  is  attached 
to  the  external  condyle  of  the  humerus;  its  lower  ends  are  attached  to  the  ulna.  The  circular  fibres  surrounding 
the  head  of  the  radius  are  called  the  orbicular  ligament. 

associated  with  it  that  it  cannot  be  ignored.  The  head  of  the  radius,  in  addition  to 
its  movements  of  flexion  and  extension  on  the  humer